End cap assembly, housing assembly, battery cell, battery and electrical device

Abstract

The present application relates to a battery cell end cap assembly, a battery cell, a shell assembly, a battery and a device using the battery cell, wherein the end cap assembly is used for the battery cell, comprising: an end cap, provided with a through hole for injecting electrolyte and a first clamping portion, the first clamping portion being arranged along the circumference of the through hole and located on the side of the end cap away from the inside of the battery cell; a sealing ring, used to seal the through hole; and a pressure relief device, covering at least part of the sealing ring and closing the through hole, and the pressure relief device is used to be destroyed when the internal pressure of the battery cell reaches a threshold value, so as to release the closure of the through hole and release the internal pressure of the battery cell; wherein the pressure relief device is rotatable, comprising a second clamping portion, when the pressure relief device rotates to the first position, the second clamping portion is clamped with the first clamping portion to limit the separation of the pressure relief device from the end cap; when the pressure relief device rotates to the second position, the second clamping portion is disengaged from the first clamping portion to achieve the separation of the pressure relief device from the end cap. Based on this, the performance of the battery cell can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an end cover assembly, a shell assembly, a battery cell, a battery and an electrical device. Background Art

[0002] Lithium-ion battery cells have been widely used in electrical devices such as electric vehicles due to their advantages of high energy density, high power density, many cycles and long storage time.

[0003] The performance of battery cells directly affects the performance of electrical devices. However, how to effectively improve the performance of battery cells has always been a difficult problem in the industry. Summary of the invention

[0004] The purpose of this application is to improve the performance of battery cells.

[0005] According to a first aspect of the present application, an end cap assembly is provided, comprising:

[0006] The end cover is provided with a through hole for injecting electrolyte and a first clamping portion, wherein the first clamping portion is arranged along the circumference of the through hole and is located on a side of the end cover away from the interior of the battery cell;

[0007] A sealing ring for sealing the through hole; and

[0008] A pressure relief device covers at least a portion of the sealing ring and closes the through hole, and the pressure relief device is used to be destroyed when the internal pressure of the battery cell reaches a threshold value to release the sealing of the through hole and release the internal pressure of the battery cell;

[0009] Among them, the pressure relief device is rotatable and includes a second clamping portion. When the pressure relief device rotates to the first position, the second clamping portion is clamped with the first clamping portion to limit the separation of the pressure relief device from the end cover; when the pressure relief device rotates to the second position, the second clamping portion is disengaged from the first clamping portion to achieve the separation of the pressure relief device from the end cover.

[0010] Since the pressure relief device is rotatably engaged with the end cover, and the engaging position is located on the side of the end cover away from the interior of the battery cell, metal chips generated when disassembling and assembling the pressure relief device are not easy to fall into the interior of the battery cell, thereby reducing the risk of short circuit caused by metal chips falling into the battery cell, thereby improving the safety of battery cell use.

[0011] In some embodiments, the pressure relief device includes a main body and a pressure relief piece, the main body is connected to the second clamping portion, the pressure relief piece closes the through hole, and the pressure relief piece is used to be destroyed when the internal pressure of the battery cell reaches a threshold to release the internal pressure.

[0012] In some embodiments, the pressure relief member is integrally or separately arranged with the main body. When integrally arranged, the structure can be simplified and the assembly is convenient. When separately arranged, it is convenient to maintain the main body and the pressure relief member separately. At the same time, it is also convenient to design different materials or structural compositions for the main body and the pressure relief member to meet the different use requirements of the main body and the pressure relief member.

[0013] In some embodiments, the pressure relief member is separately provided from the main body, and the pressure relief member is provided between the main body and the sealing ring. In this case, compared with the case where the pressure relief member is not provided between the main body and the sealing ring, but provided above the lower end surface of the main body, the pressure relief member is closer to the inside of the shell, and during the pressure relief process, the gas can impact the pressure relief member more quickly, breaking the pressure relief member, and realizing a more efficient, reliable and safe pressure relief process.

[0014] In some embodiments, the pressure relief device further includes a separation ring, which is disposed between the main body and the pressure relief member and is used to separate the main body and the pressure relief member to protect the pressure relief member. Since the separation ring is supported between the main body and the pressure relief member, the main body and the pressure relief member are separated, so that the main body and the pressure relief member are no longer in direct contact, thus reducing or even eliminating the wear of the pressure relief member during the rotation of the main body, thereby protecting the pressure relief member.

[0015] In some embodiments, the separator ring is attached to the pressure relief member. In this way, the separator ring and the pressure relief member can be pre-assembled before being assembled to the end cap assembly to improve the assembly efficiency of the battery cell.

[0016] In some embodiments, the pressure relief component includes a metal layer and a protective layer, the protective layer and the metal layer are stacked, and the ductility of the protective layer is greater than that of the metal layer. In this way, even when the metal layer is accidentally ruptured by force, the pressure relief component can still keep the through hole closed under the action of the protective layer, thereby reducing the risk of liquid leakage and gas leakage caused by accidental rupture of the metal layer, and effectively improving the reliability of the pressure relief component.

[0017] In some embodiments, the pressure relief device includes at least two pressure relief members connected to each other. When the internal pressure of the battery cell reaches a threshold, the interconnected parts of the at least two pressure relief members are opened to release the internal pressure. Since the interconnected parts of the pressure relief members have low strength, they constitute the weak parts of the pressure relief device, thus facilitating the pressure relief requirements at a smaller threshold.

[0018] In some embodiments, at least two pressure relief members are butted or partially overlapped. When butted, the interconnected parts of the pressure relief members can have a lower strength, thereby meeting the pressure relief requirements at a smaller threshold. When overlapping, it is easier to achieve connection between the pressure relief members.

[0019] In some embodiments, at least two pressure relief members partially overlap, and the overlapping portion of the at least two pressure relief members protrudes toward a side away from the sealing ring relative to the remaining portion of the at least two pressure relief members. This helps to keep the surface of the pressure relief device close to the sealing ring flat, so as to achieve more complete contact between the pressure relief device and the sealing ring.

[0020] In some embodiments, the overlapping parts of at least two pressure relief members are bent to reduce the height of the overlapping parts. The reduction of the height of the overlapping parts is conducive to reducing the height of the end cover assembly, improving the space utilization of the battery cell in the height direction, and increasing the energy density of the battery cell.

[0021] In some embodiments, a receiving groove is provided on the separation ring of the pressure relief device, and the overlapping portion of at least two pressure relief members is received in the receiving groove, thereby preventing uneven force between the main body and the pressure relief member due to the bulge of the overlapping portion.

[0022] In some embodiments, at least two pressure relief members are connected by heat sealing. When heat sealing is used, the operation is convenient, and the strength of the interconnected parts of the pressure relief members can be lower than the compressive strength of other parts of the pressure relief members, thereby meeting the explosion-proof requirements of battery cells with lower bursting pressure.

[0023] In some embodiments, the pressure relief member is an aluminum-plastic film. In this case, the aluminum-plastic film can be used to prevent electrolyte penetration and waterproof capabilities to achieve reliable sealing of the through hole under normal conditions, and the aluminum-plastic film can be used to further reduce the risk of damage and leakage caused by accidental deformation of the pressure relief member by better anti-deformation ability than a single metal sheet.

[0024] In some embodiments, the first clamping portion is one of the clamping slot and the clamping column, and the second clamping portion is the other of the clamping slot and the clamping column. The clamping slot and the clamping column cooperate with each other, and the structure is simple.

[0025] In some embodiments, the end cap assembly further comprises a guide groove, which is connected to the clamping groove, and during the rotation of the pressure relief device, the clamping column enters and exits the clamping groove through the guide groove. In this way, under the guidance of the guide groove, a smoother and more efficient rotation clamping process can be achieved.

[0026] In some embodiments, a depression groove is provided on the pressure relief device, and the sealing ring is located in the depression groove. In this way, the space occupied by the sealing ring can be reduced, which is conducive to reducing the overall height of the battery cell and improving the energy density of the battery cell.

[0027] According to a second aspect of the present application, the present application provides a housing assembly for a battery cell, comprising:

[0028] The shell is used to connect with the end cover to form the outer shell of the battery cell. The shell is provided with a through hole and a first clamping portion. The first clamping portion is arranged along the circumference of the through hole and is located on a side of the shell away from the inside of the battery cell;

[0029] A sealing ring for sealing the through hole; and

[0030] a pressure relief device, covering at least a portion of the sealing ring and closing the through hole, and configured to release the sealing of the through hole when the air pressure in the housing reaches a preset pressure;

[0031] Among them, the pressure relief device is rotatable and includes a second clamping portion. When the pressure relief device rotates to the first position, the second clamping portion is clamped with the first clamping portion to limit the separation of the pressure relief device from the shell; when the pressure relief device rotates to the second position, the second clamping portion is disengaged from the first clamping portion to achieve the separation of the pressure relief device from the shell.

[0032] The free area of ​​the shell is relatively large, which makes it more convenient to arrange the through hole, the sealing ring and the pressure relief device.

[0033] According to a third aspect of the present application, the present application provides a battery cell, comprising:

[0034] An electrode assembly and a housing for accommodating the electrode assembly, the housing comprising a shell and an end cap assembly in the embodiment of the present application, the shell having an end opening, and the end cap assembly covers the end opening of the shell; or,

[0035] An electrode assembly and a shell for accommodating the electrode assembly, the shell comprising an end cap and a shell assembly in an embodiment of the present application, the shell having an end opening, and the end cap covering the end opening of the shell.

[0036] Based on the provided end cover assembly and shell assembly, the performance of the battery cell can be effectively improved.

[0037] According to a fourth aspect of the present application, the present application provides a battery, which includes the battery cell in the embodiment of the present application. Since the performance of the battery cell is improved, the performance of the battery is improved.

[0038] According to a fifth aspect of the present application, the present application provides an electric device, which includes a battery cell in an embodiment of the present application, and the battery cell is used to provide electric energy. Since the performance of the battery cell is improved, the performance of the electric device is improved.

[0039] According to a sixth aspect of the present application, the present application provides a method for injecting liquid into a battery cell, comprising:

[0040] Injecting electrolyte into the battery cell through the through hole on the shell or end cover of the battery cell shell;

[0041] The pressure relief device is placed at a second position on the housing or the end cover, so that the pressure relief device covers at least a portion of the sealing ring, and the second clamping portion of the pressure relief device is disengaged from the first clamping portion of the housing that is arranged along the circumference of the through hole and located on a side of the housing away from the interior of the battery cell;

[0042] The pressure relief device is rotated from the second position to the first position so that the second clamping portion is clamped with the first clamping portion to limit the pressure relief device from being separated from the shell or the end cover.

[0043] Compared with the conventional method of sealing the injection hole by laser welding, this injection method can not only omit the injection hole welding sealing process, but also omit the subsequent cleaning of welding slag and drying of the residual liquid caused by welding. Therefore, the present application improves the production efficiency of battery cells.

[0044] In some embodiments, the liquid injection method further includes: before placing the pressure relief device on the housing or the end cover, installing the sealing ring on the housing. Installing the sealing ring on the housing in advance can directly cover the sealing ring after installing the pressure relief device, or generate a pressing force on the sealing ring to achieve a better sealing effect on the through hole.

[0045] In some embodiments, the injection method further comprises:

[0046] Rotate the pressure relief device from the first position to the second position to disengage the second clamping portion from the first clamping portion;

[0047] Separate the pressure relief device from the housing or end cover.

[0048] Remove the pressure relief device from the housing to facilitate maintenance operations such as filling, venting or pressure relief device replacement.

[0049] According to a fifth aspect of the present application, the present application provides a liquid injection device for a battery cell, comprising:

[0050] A liquid injection mechanism configured to inject electrolyte into the housing through a through hole provided on the housing; and

[0051] The first disassembly and assembly mechanism is configured to rotate the pressure relief device from the second position to the first position when the pressure relief device is in the second position, so that the second clamping portion of the pressure relief device and the first clamping portion on the outer shell change from a disengaged state to a clamping state, so as to limit the separation of the pressure relief device from the shell or the end cover of the outer shell.

[0052] The provided liquid injection device can flexibly and conveniently assist in the disassembly and assembly of the pressure relief device during the battery cell production and assembly and secondary liquid injection and other battery cell maintenance processes. The operation is simple, which is conducive to improving the assembly efficiency of the battery cell and shortening the maintenance time required for the battery cell, so that the battery cell can be replenished in time when the performance of the battery cell declines to ensure the working performance of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0054] Figure 1A It is a simplified schematic diagram of an electrical device in some embodiments of the present disclosure.

[0055] Figure 1B Schematic diagram of a battery in some embodiments of the present disclosure.

[0056] Figure 1C A simplified schematic diagram of a battery module in some embodiments of the present disclosure.

[0057] Figure 1D FIG. 1 is an exploded view of a battery cell in the first embodiment of the present disclosure.

[0058] Figure 2 for Figure 1D Exploded view of the mid-end cover assembly.

[0059] Figure 3A For the picture Figure 2 A perspective view of the end cap assembly is shown when the pressure relief device is in a first position.

[0060] Figure 3B for Figure 3A A top view with electrode terminals and insulating members omitted.

[0061] Figure 3C for Figure 3B AA section view.

[0062] Figure 4A for Figure 2 A perspective view of the end cap assembly is shown when the pressure relief device is in the second position.

[0063] Figure 4B for Figure 4A Top view of the .

[0064] Figure 4C for Figure 4B Partial schematic diagram when cut at BB.

[0065] Figure 5 for Figure 2 A three-dimensional view of the middle end cover.

[0066] Fig. 6A for Figure 2 A first perspective view of the mounting component is shown.

[0067] Figure 6B for Figure 2A second perspective view of the mounting component is shown.

[0068] Fig. 7A for Figure 2 A first perspective view of the pressure relief device is shown.

[0069] Figure 7B for Figure 2 A second perspective view of the pressure relief device is shown.

[0070] Figure 7C for Figure 2 A cross-sectional view of the pressure relief device shown.

[0071] Figure 8 It is an exploded view of the end cover assembly in the second embodiment of the present disclosure.

[0072] Fig. 9 for Figure 8 A three-dimensional view of the central body.

[0073] Fig. 10A for Fig. 9 A three-dimensional view of the pressure relief piece.

[0074] Fig. 10B for Fig. 10A A first variation of the pressure relief member is shown.

[0075] Fig. 10C for Fig. 10A A second variation of the pressure relief member is shown.

[0076] Fig.11 It is a stereoscopic view of the end cover assembly in the third embodiment of the present disclosure.

[0077] Fig.12 for Fig.11 Exploded view of the end cap assembly shown.

[0078] Fig.13 for Fig.12 Combination diagram of the pressure relief piece and the separation ring.

[0079] Fig.14 for Fig.13 Stereoscopic view of the center separator ring.

[0080] Fig.15 for Fig.13 A three-dimensional view of the pressure relief piece.

[0081] Fig.16 for Fig.15 A cross-sectional view of the pressure relief member shown.

[0082] Fig.17 for Fig.16 A partial enlarged view of I.

[0083] Fig.18 for Fig.17 A first variation of the pressure relief member is shown.

[0084] Fig.19 for Fig.17 A second variation of the pressure relief member is shown.

[0085] Fig. 20 It is a stereoscopic view of the end cover assembly in the fourth embodiment of the present disclosure.

[0086] Fig.21 for Fig. 20 Exploded view of the end cap assembly shown.

[0087] Fig. 22 for Fig.21 A perspective view of the installed components.

[0088] Fig.23 for Fig.21 A three-dimensional view of the pressure relief device.

[0089] Fig.24 It is a stereoscopic view of the housing assembly in some embodiments of the present disclosure.

[0090] Fig.25 Schematic diagram of the flow of the liquid injection method in some embodiments of the present disclosure.

[0091] Fig.26 Schematic diagram of the flow chart of the liquid injection method in other embodiments of the present disclosure.

[0092] Fig. 27 It is a schematic diagram of the composition of the liquid injection device in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0093] The present application is described in detail below. In the following paragraphs, different aspects of the embodiments are defined in more detail. Each aspect defined in this way can be combined with any other aspect or aspects, unless it is clearly stated that it cannot be combined. In particular, any feature that is considered to be preferred or advantageous can be combined with one or more other features that are considered to be preferred or advantageous.

[0094] The terms "first", "second", etc. that appear in this application are only for the convenience of description to distinguish different components with the same name, and do not indicate a sequence or a primary or secondary relationship.

[0095] In addition, when an element is referred to as being "on" another element, the element may be directly on the other element, or may be indirectly on the other element with one or more intermediate elements interposed therebetween. In addition, when an element is referred to as being "connected to" another element, the element may be directly connected to the other element, or may be indirectly connected to the other element with one or more intermediate elements interposed therebetween. Hereinafter, the same reference numerals represent the same elements.

[0096] There are many factors that affect the performance of battery cells. Over the years, those skilled in the art have tried to improve the structure of battery cells from many different angles to improve the performance of battery cells. However, the expected effect has not been achieved.

[0097] Secondary battery cells such as lithium-ion battery cells mainly include a housing, an electrode assembly, an adapter, and an electrolyte. The electrode assembly is arranged inside the housing and is electrically connected to the electrode terminal through the adapter. The electrode terminal is arranged in the housing for electrical connection with an external circuit. The electrolyte is injected into the housing through the injection hole to react electrochemically with the active material on the electrode sheet of the electrode assembly to generate a charge and discharge process.

[0098] In order to prevent the battery cell from exploding when the internal pressure is too high, the battery cell also includes a pressure relief member. The pressure relief member is destroyed when the internal pressure of the battery cell reaches a threshold value, thereby releasing the pressure and playing a safety protection role.

[0099] In the process of practicing the present application, the inventors found that the arrangement of the pressure relief member and the liquid injection hole also affects the performance of the battery cell, including the energy density of the battery cell, the service life and other properties.

[0100] In the related technologies known to the inventors, the exhaust channel and the injection hole corresponding to the pressure relief member are respectively provided and both are located on the end cover. The pressure relief member is fixed to the end cover by laser welding. The injection hole is closed by a separate metal seal. After the electrolyte is injected, the metal seal is fixed by laser welding to close the injection hole to prevent the electrolyte from leaking out and polluting the surrounding air and environment during use, or water vapor or metal particles from entering the battery cell, causing a short circuit between the positive and negative electrodes.

[0101] In the above arrangement, since the pressure relief piece is welded and fixed, it can only be used once. Once it is damaged, it will cause irreversible damage to the battery cell structure, causing the entire battery cell to be scrapped, affecting the service life of the battery cell.

[0102] At the same time, in the above-mentioned setting, since the injection hole is welded and sealed, it is difficult to realize the electrolyte replenishment function during the use of the battery cell, and it is difficult to meet the replenishment needs of the battery cell. After the battery cell has undergone multiple charge and discharge cycles, the internal electrolyte will inevitably undergo irreversible reaction and consumption, resulting in a decrease in the use capacity of the battery cell and a shortened service life of the battery cell. If the electrolyte inside the battery cell can be replenished during the use of the battery cell, it will effectively slow down the reduction in the capacity of the battery cell and increase the service life of the battery cell. However, in the case of a welded and sealed injection hole, the injection can only be completed during the production stage, because if you want to replenish the electrolyte during the use of the battery cell, you need to destroy the laser weld structure, which will cause irreversible damage to the battery cell structure and cause the battery cell to be scrapped.

[0103] Furthermore, in the above arrangement, since the injection hole and the exhaust channel are arranged separately, more space is required, which affects the energy density of the battery cell.

[0104] Based on the above findings, the present application improves the arrangement of the pressure relief piece and the liquid injection hole. By setting the pressure relief piece to be detachable and using the exhaust channel corresponding to the pressure relief piece as the liquid injection hole at the same time, an integrated pressure relief and liquid injection structure is formed to extend the service life of the battery cell, increase the energy density of the battery cell, and improve the performance of the battery cell.

[0105] In order to achieve the above-mentioned objectives, the present application provides an end cover assembly, a shell assembly, a battery cell, a battery, an electrical device, a liquid injection method and a liquid injection device.

[0106] Figure 1A-Figure 27 The structures of the electrical device, battery, battery cell, end cover assembly, shell assembly and liquid injection device and the process of the liquid injection method in some embodiments of the present application are shown.

[0107] For the convenience of description, we first use Figure 1D The coordinate system in is used to define various directions of the battery cell. Among them, the x-axis represents the length direction of the battery cell 400. The Y-axis is perpendicular to the x-axis in the horizontal plane, and represents the width direction of the battery cell 400. The Z-axis is perpendicular to the plane formed by the x-axis and the y-axis, and represents the height direction of the battery cell 400. Based on this orientation definition, descriptions of orientations or positional relationships indicated by "up", "down", "top", "bottom", "front", "back", "inside" and "outside" are used, but it should be understood that this orientation definition is only for the convenience of describing the present application, and does not indicate or imply that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present application.

[0108] Next, combine Figure 1A-Figure 27 This application is described.

[0109] Figure 1A The structure of the electric device 100 in some embodiments is shown. Figure 1A The electric device 100 is a device that uses a battery cell 400 as a power source, and includes a battery cell 400, and the battery cell 400 is used to provide electric energy.

[0110] The electric device 100 may be a mobile device such as a vehicle 101, a ship or a small aircraft, and includes a power source, which includes a battery cell 400, and the battery cell 400 provides driving force for the electric device 100. In some embodiments, the driving force of the electric device 100 is all electric energy, in which case the power source only includes the battery cell 400. In other embodiments, the driving force of the electric device 100 includes electric energy and other energy sources (such as mechanical energy), in which case the power source includes the battery cell 400 and other equipment such as an engine.

[0111] Take the case where the electric device 100 is a vehicle 101 as an example. Figure 1A In some embodiments, the power-consuming device 100 is a new energy vehicle such as a pure electric vehicle, a hybrid electric vehicle or an extended-range vehicle, which includes a battery cell 400, a controller 104 and a power device 102 such as a motor 103. The battery cell 400 is electrically connected to the power device 102 such as the motor 103 through the controller 104, so that the battery cell 400 can supply power to the power device 102 such as the motor 103 under the control of the controller 104.

[0112] In order to make the battery cell reach a higher power to meet higher usage requirements, the battery 200 may be provided in the power-consuming device 100. Figure 1B and Figure 1C The battery 200 includes at least two battery cells 400 , so that more electric energy can be provided compared to the case where a single battery cell 400 is provided.

[0113] like Figure 1B and Figure 1C As shown, in some embodiments, the battery 200 includes a housing 500 and a plurality of battery cells 400, and the plurality of battery cells 400 are disposed inside the housing 100. The plurality of battery cells 400 may also be combined into a battery module 300, and then the plurality of battery modules 300 may be combined into a battery 200.

[0114] like Figure 1B As shown, in some embodiments, the box 500 includes a first box 501 and a second box 502. The first box 501 and the second box 502 are engaged with each other, so that a closed space is formed inside the box 500 to accommodate the battery cell 400.

[0115] Combination Figure 1B and Figure 1CIt can be seen that in some embodiments, the number of battery cells 400 is multiple, and the multiple battery cells 400 are arranged in groups, and each group of battery cells 400 is called a battery module 300. In other words, the battery 200 includes at least two battery modules 300, all battery modules 300 are arranged in the box 500, and each battery module 300 includes at least two battery cells 400. It should be noted that Figure 1B The battery module 300 is simplified. Figure 1C The battery cells 400 in the battery module 300 are shown in a simplified manner.

[0116] The battery cells 400 in the battery module 300 can be electrically connected in series, parallel or hybrid to achieve a larger capacity or power. Figure 1C In some embodiments, the battery 400 is placed vertically, in which case the height direction of the battery cell 400 is consistent with the vertical direction, and the battery cells 400 in the battery module 300 are arranged side by side along the width direction of the battery cell 400. For another example, in some other embodiments, the battery cell 400 is placed horizontally, in which case the width direction of the battery cell 400 is consistent with the vertical direction, and the battery cells 400 in the battery module 300 can be stacked in at least one layer along the width direction of the battery cell 400, and each layer includes at least two battery cells 400 spaced apart along the length direction.

[0117] It can be seen that in the electric device 100 and the battery 200, the battery cell 400 is the core structure, and the performance of the battery cell 400 directly affects the performance of the electric device 100 and the battery 200. When the life of the battery cell 400 is extended and the performance is improved, it is beneficial to extend the life of the electric device 100 and the battery 200 and improve the performance of the electric device 100 and the battery 200.

[0118] Next, we will combine Figure 1D-Figure 24 The structure of the battery cell 400 is described.

[0119] Figure 1D The overall structure of the battery cell 400 in some embodiments is shown. Figure 1D The battery cell 400 may be a square battery cell or a cylindrical battery cell, and includes a housing 70, an electrode assembly 30, an isolating member 40, a connecting member 20, and the like.

[0120] The housing 70 is used to accommodate the electrode assembly 30, etc., to provide protection for the electrode assembly 30, etc. The housing 70 includes a shell 7 and an end cap assembly 10. The shell 7 has an end opening 71. The end cap assembly 10 covers the end opening 71 of the shell 7, so that a closed space for accommodating the electrode assembly 30, etc. is formed inside the housing 70.

[0121] The electrode assembly 30 is used to generate electric energy. It is arranged in the housing 70 and is formed by stacking or winding a first electrode sheet, a second electrode sheet, and an insulating spacer between the first electrode sheet and the second electrode sheet. One of the first electrode sheet and the second electrode sheet is a positive electrode sheet, and the other is a negative electrode sheet, and both have a coating portion coated with an active material and a pole ear 301 extending outward from the coating portion and not coated with an active material. The electric energy generated by the electrode assembly 30 is transmitted outward through the pole ear 301. Among them, the pole ear 301 corresponding to the positive electrode sheet can be called a positive pole ear, and the pole ear 301 corresponding to the negative electrode sheet is called a negative pole ear. The positive pole ear extends from the coating portion of the positive electrode sheet, and the negative pole ear extends from the coating portion of the negative electrode sheet. In some cases, such as in some square battery cells, the positive pole ear and the negative pole ear are located at the same end of the electrode assembly 300. In other cases, such as in some cylindrical battery cells, the positive pole ear and the negative pole ear are located at opposite ends of the electrode assembly 300.

[0122] According to actual use requirements, the number of electrode assemblies 30 in the battery cell 400 can be one, two, or more.

[0123] The isolating member 40 is disposed in the outer shell 70 and is located between the electrode assembly 30 and the shell 7 , and is used to insulate the electrode assembly 30 from the shell 7 to prevent a short circuit between the electrode assembly 30 and the shell 7 .

[0124] The adapter 20 is disposed in the housing 70 and is located between the electrode assembly 30 and the end cap assembly 10, and is used to realize the electrical connection between the electrode assembly 30 and the electrode terminal 10c of the end cap assembly 10. Figure 1D and Figure 2 In some embodiments, the end cap assembly 10 includes two electrode terminals 10c, and the two electrode terminals 10c correspond to the positive electrode ear and the negative electrode ear, respectively, and can be called the positive terminal and the negative terminal, respectively. At this time, the battery cell 400 includes two adapters 20, and the two adapters 20 correspond to the two electrode terminals 10c one by one, and are respectively used to realize the electrical connection between the positive terminal and the positive electrode ear, and the electrical connection between the negative terminal and the negative electrode ear. As a variation, in some other embodiments, the end cap assembly 10 may also include only one electrode terminal 10c, but the battery cell 400 includes two end cap assemblies 10, and the two end cap assemblies 10 are respectively arranged on opposite sides of the electrode assembly 30.

[0125] Figure 2-Figure 23 The more specific structure of the end cap assembly 10 in some embodiments is shown. Figure 2-23 The structure of the end cover assembly 10 is further described.

[0126] Reference Figure 2-23 In some embodiments, the end cover assembly 10 includes an end cover 10a, an insulating member 10d, a sealing ring 3 and a pressure relief device 10b.

[0127] The end cap 10a is used to cover the end opening 71 of the housing 7 and provide a mounting base for other structural parts of the end cap assembly 10, such as the electrode terminal 10c and the pressure relief device 10b. The end cap 10a is provided with a through hole 11 for injecting electrolyte. The through hole 11 penetrates the opposite two side surfaces of the end cap 10a so that the electrolyte can be injected into the battery cell 400 through the through hole 11. The shape of the through hole 11 is not limited, for example, it can be a circular hole, an elliptical hole, a polygonal hole or a hole of other shapes.

[0128] The insulating member 10 d is disposed between the end cap 10 a and the electrode assembly 30 to achieve insulation between the end cap 10 a and the electrode assembly 30 .

[0129] The sealing ring 3 is disposed on the end cover 10a and is used to seal the through hole 11 to prevent leakage of the electrolyte.

[0130] The pressure relief device 10b is arranged on the end cover 10a, and is used to cover at least part of the sealing ring 3 and close the through hole 11. When the internal pressure of the battery cell 400 reaches a threshold, the pressure relief device 10b is destroyed to release the sealing of the through hole 11, release the internal pressure of the battery cell 400, and play a role in safety and explosion prevention.

[0131] The threshold value may depend on one or more materials of the positive electrode sheet, the negative electrode sheet, the electrolyte and the insulating spacer in the battery cell 400 , and the specific size may vary according to different design requirements.

[0132] The destruction of the pressure relief device 10b means that the pressure relief device 10b is in action or activated to a certain state, for example, at least a portion of the pressure relief device 10b is ruptured, broken, torn or opened, etc., so that the internal pressure and temperature of the battery cell 400 can be released.

[0133] The pressure relief device 10b may be in the form of a structure such as an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, and may specifically be a pressure-sensitive or temperature-sensitive element or structure, so that when the internal pressure or temperature of the battery cell 400 reaches a set threshold, the pressure relief device 10b performs an action, or the weak part of the pressure relief device 10b is destroyed, thereby forming an opening or channel for the internal pressure or temperature to be released. After the pressure relief device 10b is destroyed, the high-temperature and high-pressure substances inside the battery cell 400 will be discharged from the destroyed part of the pressure relief device 10b as emissions, so that the pressure and temperature of the battery cell 400 can be released under controllable pressure or temperature, thereby avoiding potential more serious accidents.

[0134] Based on the above arrangement, an integrated pressure relief and liquid injection structure is formed on the end cap assembly 10. Since the through hole 11 is used as both a liquid injection hole and an exhaust channel, the liquid injection and exhaust functions are integrated into one. Therefore, there is no need to separately set up the liquid injection hole and the exhaust channel, which can effectively reduce the space occupation and improve the energy density of the battery cell 400. At the same time, since the pressure relief device 10b is used as both an explosion-proof device and a liquid injection hole seal, it integrates the explosion-proof pressure relief and liquid injection sealing functions. Therefore, there is no need to separately set up a metal seal for the liquid injection hole, which is conducive to simplifying the structure of the battery cell 400.

[0135] In order to facilitate the disassembly and assembly of the pressure relief device 10 b and to extend the service life of the battery cell 400 , in some embodiments, the pressure relief device 10 b and the end cover 10 a are configured to be rotatably connected.

[0136] Among them, refer to Figure 2-23 , a first clamping portion 24 is provided on the end cover 10a, and the first clamping portion 12 is arranged along the circumference of the through hole 11. At the same time, the pressure relief device 10b is rotatable and includes a second clamping portion 42 that cooperates with the first clamping portion 24. When the pressure relief device 10b rotates to the first position, the second clamping portion 42 is clamped with the first clamping portion 24 to limit the separation of the pressure relief device 10b from the end cover 10a. When the pressure relief device 10b rotates to the second position, the second clamping portion 42 is disengaged from the first clamping portion 24 to achieve the separation of the pressure relief device 10b from the end cover 10a. Specifically, in some embodiments, the pressure relief device 10b rotates relative to the end cover 10a in a plane perpendicular to the height direction of the battery cell 400, and the rotation axis is the axis of the through hole 11.

[0137] Based on the above arrangement, it is only necessary to control the pressure relief device 10b to rotate relative to the end cover 10a between the first position and the second position, and the engagement or disengagement between the first clamping portion 24 and the second clamping portion 42 can be utilized to achieve the combination or separation between the pressure relief device 10b and the end cover 10a, so as to disassemble and assemble the pressure relief device 10b.

[0138] Among them, when the pressure relief device 10b rotates to the first position relative to the end cover 10a, and the first clamping portion 24 is engaged with the second clamping portion 42, the pressure relief device 10b is combined with the end cover 10a, and the pressure relief device 10b is firmly installed on the end cover 10a, and the through hole 11 is blocked to prevent liquid leakage or external impurities from entering the battery cell 400. At this time, due to the restriction of the end cover 10a, the pressure relief device 10b cannot move relative to the end cover 10a in the direction away from the electrode assembly 30, so that the pressure relief device 10b will not fall off from the end cover 10a. In addition, in some embodiments, the pressure relief device 10b in the first position squeezes the sealing ring 3, increases the deformation of the sealing ring 3, and enables the sealing ring 3 to achieve a better sealing effect. In other embodiments, the pressure relief device 10b in the first position does not squeeze the sealing ring 3, but only contacts with the sealing ring 3, which plays a role in limiting the displacement of the sealing ring 3 in the height direction.

[0139] When the pressure relief device 10b rotates to the second position relative to the end cover 10a and the first clamping portion 24 is disengaged from the second clamping portion 42, the end cover 10a no longer restricts the pressure relief device 10b from moving toward the side away from the electrode assembly 30, and the pressure relief device 10b can therefore be removed from the end cover 10a.

[0140] Removing the pressure relief device 10b not only facilitates the replacement of the pressure relief device 10b that has been damaged or has been difficult to maintain to the threshold value due to premature creep, but also reduces the life requirement of the pressure relief device 10b and improves the reliability of the pressure relief device 10b; at the same time, it can also release the blockage of the through hole 11 by the pressure relief device 10b, so that the through hole 11 can connect the inside and outside of the battery cell 400. At this time, on the one hand, electrolyte can be added to the battery cell 400 through the through hole 11 to realize the secondary liquid injection function, so that during the use of the battery cell 400, the electrolyte can be conveniently and timely replenished or replaced for the battery cell 400, so as to effectively slow down the reduction of the capacity of the battery cell 400 and extend the service life of the battery cell 400. On the other hand, the gas inside the battery cell 400 can also be discharged through the through hole 11 to realize the exhaust process.

[0141] Among them, the gas inside the battery cell 400 discharged through the through hole 11 may include the gas generated during the use of the battery cell 400. By discharging the gas generated during the use of the battery cell 400, the internal pressure of the shell 70 can be released, and the pressure relief device 10b is prevented from creeping prematurely due to the continuous effect of the gas generated on the pressure relief device 10b, so as to avoid the battery cell 400 from leaking liquid or ingesting water and air due to the premature creep of the pressure relief device 10b, which is conducive to extending the service life of the pressure relief device 10b, and further conducive to extending the service life of the battery cell 400. At the same time, discharging the gas generated in the shell 70 can also reduce the force exerted by the expansion of the battery cell 400 on other structures, and avoid other structures from being damaged due to excessive expansion force of the battery cell 400, which is conducive to further improving the service life of the battery 200 and the electrical device 100 using the battery cell 400.

[0142] Based on the above configuration, after the pressure relief device 10b has been used for a period of time, the pressure relief device 10b can be removed to discharge the gas inside the battery cell 400, thereby reducing the service life requirements of the pressure relief device 10b and improving the reliability of the pressure relief device 10b. In addition, after the pressure relief device 10b is removed, a secondary fluid replenishment can be performed to improve the performance of the battery cell 400 and extend the service life of the battery cell 400. At the same time, when the pressure relief device 10b is reinstalled, a new pressure relief device 10b can be replaced to further improve the reliability of the battery cell 400 and extend the service life of the battery cell 400.

[0143] It can be seen that the above-mentioned setting method can realize the detachable setting of the pressure relief device 10b, and the disassembly is convenient and fast, and it will not cause irreversible damage to the battery cell 400, so that the battery cell 400 can be reused, thereby extending the service life of the battery cell 400; and, in the process of disassembling and assembling the pressure relief device 10b, liquid injection and exhaust can be carried out to improve the reliability of the battery cell 400 and extend the service life of the battery cell 400; in addition, it can also realize the efficient use of the space of the end cover 10a, save the space occupied when a single liquid injection hole is set, and improve the energy density of the battery cell 400; at the same time, because the flow area of ​​the general exhaust channel is larger than the area of ​​the liquid injection hole, therefore, the through hole 11 used for exhaust is used as the liquid injection hole at the same time, which is also conducive to increasing the liquid injection area, improving the liquid injection efficiency, speeding up the production rhythm, and increasing production capacity.

[0144] Therefore, the pressure relief device 10b is set to be rotatably snap-fitted, and the through hole 11 corresponding to the pressure relief device 10b for exhaust is also used as a liquid injection hole. This allows the pressure relief device 10b to be quickly disassembled and assembled without causing irreversible damage to the battery cell 400, thereby facilitating liquid injection and exhaust, effectively improving the energy density of the battery cell 400, extending the service life of the battery cell 400, and improving the performance of the battery cell 400.

[0145] The pressure relief device 10b is set to be detachable, so that when necessary, for example, when the pressure relief device 10b has been damaged, or when the pressure relief device 10b has not been damaged but has worked for a preset time, the pressure relief device 10b can be disassembled to replace the pressure relief device 10b, or to perform battery cell maintenance operations such as injection or exhaust. In addition, when the pressure relief device 10b is disassembled, no irreversible damage will be caused to the battery cell 400, so that the appearance of the battery cell 400 can be kept consistent before and after disassembly, and the use after injection and exhaust will not be affected. At the same time, after the injection and exhaust are completed, the pressure relief device 10b can be easily installed on the end cover 10a, and the through hole 11 can be reliably closed again to ensure the working reliability of the battery cell 400 after injection and exhaust. In addition, because the through hole 11 is directly closed by rotating the pressure relief device 10b, it is no longer necessary to achieve the sealing of the through hole 11 by laser welding, which can reduce the cleaning steps of the through hole 11 before laser welding, which is conducive to improving the production efficiency of the battery cell 400.

[0146] Although in order to achieve the detachable setting of the pressure relief device 10b, the pressure relief device 10b can also be connected to the end cover 10a by other methods such as threaded connection, when the rotary clamping method is adopted, the matching accuracy requirements of the pressure relief device 10b and the end cover 10a are relatively low, which is convenient for processing; at the same time, the operation is simpler and more convenient, which is conducive to achieving a more efficient disassembly and assembly process, which is conducive to improving the assembly efficiency of the battery cell 400 during production and shortening the maintenance time during the use of the battery cell 400; and, since the rotary clamping method does not require a sufficient number of threads for connection like the threaded connection method, therefore, compared with the threaded connection method, the rotary clamping method does not need to occupy too much height space, and the height requirement of the end cover assembly 10 is lower, which is conducive to reducing the height of the battery cell 400, improving the height space utilization of the battery cell 400, and increasing the energy density of the battery cell 400.

[0147] In addition, when the threaded connection is adopted, metal chips generated by friction during the screwing process of the screw member are likely to fall directly into the battery cell 400, causing a short circuit inside the battery cell 400. When the rotary clamping method is adopted, the risk of short circuit caused by falling metal chips can be reduced by setting a rotary clamping structure.

[0148] For example, refer to Figure 2-23In some embodiments, the first clamping portion 24 is located on the side of the end cap 10a away from the inside of the battery cell 400 (i.e., the side away from the housing 7, i.e., the side away from the electrode assembly 30). In other words, the first clamping portion 24 is not directly disposed on the surface of the end cap 10a facing the inside of the battery cell 400 (also the surface of the end cap 10a close to the electrode assembly 30), but has a preset distance from the surface of the end cap 10a facing the inside of the battery cell 400. The size of the "preset distance" here is not specifically limited. For example, the first clamping portion 24 can be disposed in the upper region, middle region, or lower region of the end cap 10a, so that at least part of the end cap 10a is located between the first clamping portion 24 and the electrode assembly 30.

[0149] During the rotation of the pressure relief device 10b, friction may occur between the first clamping portion 24 and the second clamping portion 42, generating metal particles. By arranging the first clamping portion 24 on the side of the end cover 10a away from the inside of the battery cell 400, it is helpful to prevent the metal particles generated during the rotation from directly falling into the housing 7 and causing the battery cell 400 to short-circuit, which can effectively improve the working safety of the battery cell 400.

[0150] Among them, refer to Figure 2-4C In some embodiments, in the height direction, the first clamping portion 24 is not lower than the position of the sealing ring 3, so that the rotation clamping position is not lower than the position of the sealing surface, and the metal chips generated during the rotation friction process can be blocked by the sealing ring 3, so that they cannot fall into the housing 7, and after the pressure relief device 10b is removed, the metal chips can be easily cleaned, and the metal chips can be more reliably prevented from falling. At the same time, the rotation clamping position is not lower than the position of the sealing surface, which also facilitates the pressure relief device 10b to apply force to the sealing ring 3 during the rotation process, increase the deformation of the sealing ring 3, and improve the sealing effect of the sealing ring 3.

[0151] In addition, refer to Figure 4C In some embodiments, a depression 412 is provided on the pressure relief device 10b, and the sealing ring 3 is located in the depression 412. In this way, the height occupied by the sealing ring 3 can be reduced, thereby reducing the overall height of the end cap assembly 10 and improving the energy density of the battery cell 400.

[0152] Next, the structural composition of the pressure relief device 10b will be further introduced.

[0153] Reference Figure 2-23In some embodiments, the pressure relief device 10b includes a main body 4 and a pressure relief member 5, the main body 4 is connected to the second clamping portion 42, the pressure relief member 5 closes the through hole 11, and is used to be destroyed when the internal pressure of the battery cell 400 reaches a threshold value to release the internal pressure. In this way, the main body 4 can be used to drive the second clamping portion 42 to rotate to achieve the rotation clamping function, and the pressure relief member 5 can be used to achieve the pressure relief function.

[0154] Among them, refer to Figure 2-7C as well as Figure 20-23 The main body 4 and the pressure relief member 5 can be provided integrally to simplify the structure and facilitate assembly; or, referring to Figure 8-19 The main body 4 and the pressure relief component 5 can also be separately arranged, so that it is convenient to maintain the main body 4 and the pressure relief component 5 separately. For example, when the pressure relief component 5 is damaged and the main body 4 is not damaged, only the pressure relief component 5 can be replaced to save maintenance costs. At the same time, it is also convenient to design different materials or structural compositions for the main body 4 and the pressure relief component 5 to meet the different usage requirements of the main body 4 and the pressure relief component 5. For example, the thickness of the pressure relief component 5 can be flexibly changed to adjust the pressure resistance of the pressure relief component 5 and achieve bursting pressure relief under different thresholds.

[0155] When the main body 4 and the pressure relief member 5 are separately provided, refer to Figure 8-19 , the pressure relief member 5 can be arranged between the main body 4 and the sealing ring 3. At this time, compared with the case where the pressure relief member 5 is not arranged between the main body 4 and the sealing ring 3, but is arranged at other positions such as above the lower end surface of the main body 4, the pressure relief member 5 is closer to the inside of the shell 7. During the pressure relief process, the gas can impact the pressure relief member 5 more quickly, breaking the pressure relief member 5, and realizing a more efficient and reliable safe pressure relief process. In addition, the pressure relief member 5 located between the main body 4 and the sealing ring 3 can cover the sealing ring 3. Since the pressure relief member 5 can be arranged to have a cross-sectional area greater than that of the main body 4, the pressure relief device 10b covers the sealing ring 3 through the pressure relief member 5 instead of the main body 4, which is conducive to achieving a more sufficient contact between the pressure relief device 10b and the sealing ring 3, and more reliable squeezing and / or limiting of the sealing ring 3.

[0156] Continue to refer to Figure 8-19 When the pressure relief component 5 is located between the main body 4 and the sealing ring 3, in some embodiments, the pressure relief device 10b further includes a separating ring 6, which is disposed between the main body 4 and the pressure relief component 5 to separate the main body 4 and the pressure relief component 5 to protect the pressure relief component 5.

[0157] Since the separation ring 6 is supported between the main body 4 and the pressure relief member 5, the main body 4 and the pressure relief member 5 are separated, so that the main body 4 and the pressure relief member 5 are no longer in direct contact, thus reducing or even eliminating the wear of the pressure relief member 5 during the rotation of the main body 4, thereby protecting the pressure relief member 5. At the same time, the middle part of the separation ring 6 is hollowed out, and the injection channel and the exhaust channel will not be blocked, which facilitates the smooth implementation of the injection process and the exhaust process.

[0158] The separator ring 6 can be attached to the pressure relief member 5, for example, the separator ring 6 can be bonded to the pressure relief member 5, or connected via a connector. In this way, the separator ring 6 and the pressure relief member 5 can be pre-assembled before being assembled to the end cap assembly 10a to improve the assembly efficiency of the battery cell 400.

[0159] The structure of the pressure relief member 5 can be varied.

[0160] As one of them, the pressure relief member 5 can be a single-layer member. Figure 2-7C , Figure 8-10A as well as Figure 20-23 In some embodiments, the pressure relief member 5 only includes the metal layer 51. In this case, the structure of the pressure relief member 5 is relatively simple.

[0161] As another example, the pressure relief member 5 may also be a two-layer or multi-layer structure. Fig. 10B , Fig. 10C as well as Fig.17 and Fig.19 In some embodiments, the pressure relief member 5 includes a metal layer 51 and a protective layer 52a, the protective layer 52a and the metal layer 51 are stacked, and the ductility of the protective layer 52a is greater than the ductility of the metal layer 51. In this way, even when the metal layer 51 is accidentally ruptured by force, the pressure relief member 5 can still keep the through hole 11 closed under the action of the protective layer 52a, thereby reducing the risk of liquid leakage and gas leakage caused by the accidental rupture of the metal layer 51, and effectively improving the reliability of the pressure relief member 5.

[0162] Specifically, the protective layer 52a may be a single-layer structure, and may be disposed on a side of the metal layer 51 close to the electrode assembly 30, or may be disposed on a side of the metal layer 51 away from the electrode assembly 30; or, the protective layer 52a may be a two-layer or multi-layer structure to more fully protect the metal layer 51. Fig. 10B and Fig. 10CIn some embodiments, the protective layer 52a includes a first protective layer 521 and a second protective layer 522. The first protective layer 521 is disposed on the side of the metal layer 51 away from the electrode assembly 30, and the second protective layer 522 is disposed on the side of the metal layer 51 close to the electrode assembly 30. At this time, the first protective layer 521 and the second protective layer 522 sandwich the metal layer 51, and the metal layer 51 is located inside the protective layer 52a. In this way, the protective layer 52a can provide double-layer protection for the metal layer 51 on both sides of the thickness of the metal layer 51, with better protection effect, and can more reliably reduce the risk of accidental liquid leakage and gas leakage.

[0163] As a specific embodiment of the multi-layer pressure relief component 5, the pressure relief component 5 can be an aluminum-plastic film 52. The aluminum-plastic film 52 is a multi-layer thin film structure, which generally includes an outer resistance layer, a barrier layer and a high barrier layer arranged in sequence from the outside to the inside, and the layers can be bonded. Among them, the outer resistance layer is also called the base layer, which is mainly made of nylon or PET (Polyethylene terephthalate, polyethylene terephthalate) material, and can protect the barrier layer from being scratched. The barrier layer is generally an aluminum layer, which can play a role in shaping and waterproofing. The high barrier layer is also called the electrolyte resistant layer, which is mainly made of polypropylene material. Due to its high barrier properties, insulation and electrolyte resistance and other advantages, in the related art, the aluminum-plastic film 52 is generally used as one of the core materials for the packaging of soft-pack battery cells, and plays a role in protecting the internal electrode assembly 30. However, the present application breaks the conventional use of the aluminum-plastic film 52 and uses the aluminum-plastic film 52 as the pressure relief component 5, and specifically uses the outer resistance layer, the barrier layer and the high barrier layer of the aluminum-plastic film 52 as the aforementioned first protective layer 521, the metal layer 522 and the second protective layer 523, respectively. Not only can the strong electrolyte penetration and waterproof capabilities of the aluminum-plastic film 52 be utilized to achieve reliable sealing of the through hole 11 under normal conditions, but the aluminum-plastic film 52 can also be utilized to have a better anti-deformation ability than a single metal sheet to further reduce the risk of damage and leakage due to accidental deformation of the pressure relief component 5.

[0164] In addition, the number of the pressure relief members 5 is not limited, and can be one, two, or more. When the pressure relief device 10 includes at least two pressure relief members 5, refer to Figure 11-19 The at least two pressure relief members 5 can be connected to each other, and when the internal pressure of the battery cell 400 reaches a threshold, the interconnected parts of the at least two pressure relief members 5 are opened to release the internal pressure. At this time, the strength of the interconnected parts of the pressure relief members 5 is relatively low, constituting a weak part of the pressure relief device 10b, so as to meet the pressure relief requirements at a lower threshold.

[0165] Among them, refer to Fig.19In some embodiments, the at least two pressure relief members 5 may be butted against each other, that is, connected without overlapping. In this case, the interconnected parts of the pressure relief members 5 may have a lower strength, thereby meeting the pressure relief requirements at a smaller threshold.

[0166] Or, refer to Fig.17 and Fig.18 In some other embodiments, the at least two pressure relief members 5 may also partially overlap each other. In this case, it is easier to achieve the connection between the pressure relief members 5.

[0167] Continue to refer to Figure 17-18 In some embodiments, when at least two pressure relief parts 5 partially overlap, the overlapping portion 524 of the at least two pressure relief parts 5 protrudes toward a side away from the sealing ring 3 relative to the remaining portions of the at least two pressure relief parts 5, which is beneficial for keeping the surface of the pressure relief device 10b close to the sealing ring 3 flat, so as to achieve more complete contact between the pressure relief device 10b and the sealing ring 3.

[0168] Among them, refer to Fig.17 In some embodiments, the overlapping portion 524 is bent, specifically, the overlapping portion 524 is bent toward the side close to the sealing ring 3. In this way, the height of the overlapping portion 524 can be reduced. The reduction in the height of the overlapping portion 524 is conducive to reducing the height of the end cap assembly 10, improving the space utilization of the battery cell 400 in the height direction, and increasing the energy density of the battery cell 400.

[0169] In addition, when the pressure relief device 10b includes a separation ring 6, refer to Figure 13-15 In some embodiments, the separation ring 6 is provided with a receiving groove 61, and the overlapping portion 524 is received in the receiving groove 61. Based on this, it is possible to prevent uneven force between the main body 4 and the pressure relief member 5 due to the bulge of the overlapping portion 524.

[0170] In the above embodiments, various connection methods such as bonding or heat sealing can be used between the pressure relief members 5. Among them, when heat sealing is used, the operation is convenient, and the strength of the interconnected parts of the pressure relief members 5 can be made lower than the compressive strength of other parts of the pressure relief members, thereby meeting the explosion-proof requirements of battery cells with lower explosion pressure.

[0171] In addition, based on the above embodiments, a notch 53 may be further provided on the pressure relief member 5. The notch 53 may constitute a weak area of ​​the pressure relief member 5, so that when the internal pressure of the battery cell 400 reaches a threshold value, the pressure relief member 5 can be first destroyed at the notch 53, thereby reducing the difficulty of destroying the pressure relief member 5, and realizing directional exhaust and pressure relief of the battery cell 400, further improving the safety of the battery cell 400.

[0172] The notch 53 may be a groove of various shapes such as a cross-shaped groove 532 or an annular groove 531. Furthermore, when the notch 53 is an annular groove 531, the annular groove 531 may be a full-circle annular groove or a non-full-circle annular groove. For example, in some embodiments, the annular groove 531 is a 3 / 4-circle annular groove. In this way, when the notch 53 is broken, it will not be completely separated from the rest of the pressure relief member 5, but can still maintain a connection with the rest of the pressure relief member 5, so that the notch 53 will not fly out directly and cause other damage, thereby improving the safety of the pressure relief process.

[0173] In addition, refer to Figure 4C In some embodiments, the notch 53 is located radially inward of the inner ring of the sealing ring 3. In other words, in the radial direction of the sealing ring 3, the outer edge of the notch 53 is located inward of the inner ring of the sealing ring 3, and the outer edge of the notch 53 does not exceed the inner ring of the sealing ring 3. In this case, the notch 53 will not be affected by the rebound force of the sealing ring 3, so the notch 53 can be prevented from being accidentally broken due to the rebound force of the sealing ring 3, which is conducive to improving the reliability of the pressure relief member 5 and extending the service life of the pressure relief member 5.

[0174] Next, the rotational clamping structure of the pressure relief device 10b and the end cover 10a is further introduced.

[0175] As mentioned above, the pressure relief device 10b and the end cover 10a are rotatably connected based on the cooperation between the first clamping portion 24 on the end cover 10a and the second clamping portion 42 on the pressure relief device 10b. When one of the first clamping portion 24 and the second clamping portion 42 is a clamping groove 24a, the other is a clamping column 42a. In other words, when the first clamping portion 24 is one of the clamping groove 24a and the clamping column 42a, the second clamping portion 42 is the other of the clamping groove 24a and the clamping column 42a. For example, referring to Figure 2-23 In some embodiments, the first clamping portion 24 is a clamping groove 24a, and the second clamping portion 42 is a clamping column 42a. In this case, the processing of the clamping groove 24a and the clamping column 42a is more convenient.

[0176] Further, refer to Figure 2-23 In some embodiments, the end cap assembly 10 further includes a guide groove 25, which is in communication with the card slot 24a. During the rotation of the pressure relief device 10b, the card column 42a enters and exits the card slot 24a through the guide groove 25. In this way, on the one hand, the guide groove 25 can avoid the pressure relief device 10b in the second position to prevent the pressure relief device 10b from interfering with the end cap 10a in the second position. On the other hand, the guide groove 25 can also guide the card column 42a to enter and exit the card slot 24a more smoothly during the rotation of the pressure relief device 10b, so as to achieve a smoother and more efficient rotation and clamping process.

[0177] In order to facilitate the arrangement of the first clamping portion 24 on the end cover 10a, refer to Figure 2-23 In some embodiments, the end cap 10a includes not only an end cap body 1, but also a mounting component 2. The end cap body 1 is used to cover the end opening 71 of the shell 7. The mounting component 2 is arranged on the end cap body 1, and is specifically located on the side of the end cap body 1 away from the electrode assembly 30, and there is a gap between the mounting component 2 and the surface of the end cap body 1 facing the electrode assembly 30. The through hole 11 sequentially penetrates the mounting component 2 and the end cap body 1, and includes a first hole segment 111 located on the end cap body 1 and a second hole segment 26 located on the mounting component 2. The first hole segment 111 and the second hole segment 26 are sequentially arranged along the direction from the inside to the outside of the battery cell 400, and are connected to each other, so that when the electrolyte is poured, the electrolyte can flow through the second hole segment 26 and the first hole segment 111 in sequence and enter the shell 7. The first clamping portion 24 is arranged on the mounting component 2, or the first clamping portion 24 is formed by the mounting component 2 and the end cap body 1.

[0178] Since the thickness of the end cover body 1 is generally thin, it is difficult to directly process the first clamping portion 24 on the end cover body 1. However, by further providing a mounting component 2 connected to the end cover body 1, and setting the first clamping portion 24 on the mounting component 2, or setting the first clamping portion 24 between the mounting component 2 and the end cover body 1, the processing difficulty of the first clamping portion 24 can be effectively reduced, and the setting of the first clamping portion 24 on the end cover 10a can be conveniently achieved.

[0179] Specifically, refer to Figure 2-19 In some embodiments, the main body 4 of the pressure relief device 10b is inserted into the second hole section 26, and the first clamping portion 24 is disposed on the inner wall of the mounting component 2, and the second clamping portion 42 is disposed on the outer wall of the main body 41. Alternatively, referring to Figure 20-23 In some other embodiments, the main body 4 is sleeved on the outside of the mounting component 2, and the first clamping portion 24 is arranged on the outer wall of the mounting component 2, and the second clamping portion 42 is arranged on the inner wall of the main body 41. In both cases, the first clamping portion 24 and the second clamping portion 42 can be combined or disengaged with the rotation of the pressure relief device 10b, so as to realize the disassembly and assembly of the pressure relief device 10b on the end cover 10a. Among them, when the main body 4 is inserted into the second hole section 26, it is beneficial to reduce the height of the pressure relief device 10b protruding from the end cover 10a, which can improve the utilization rate of the height direction space of the battery cell 400 and improve the energy density of the battery cell 400; on the other hand, it can also reduce the possibility of the pressure relief device 10b colliding with other components during the installation or use of the battery cell 400; on the other hand, when the battery cell 400 is used in the battery 200 or the electrical device 100, it is also convenient to reserve space above the battery cell 400 for installing other structural components such as the signal detection circuit.

[0180] It can be seen that in the present application, the pressure relief device 10b can be quickly disassembled and assembled, which is convenient for liquid injection and exhaust, and can effectively improve the performance of the battery cell 400. The maintenance process does not need to irreversibly destroy the battery cell 400 and does not affect the appearance of the battery cell 400.

[0181] Next, we will combine Figure 1D-23 The embodiments shown are used to further illustrate the solutions of the present application.

[0182] First of all Figure 1D-Figure 7C The first embodiment shown will be described.

[0183] like Figure 1D As shown, in this embodiment, the battery cell 400 is a square battery cell, which includes an electrode assembly 30 and a shell 70 for accommodating the electrode assembly 30. The shell 70 includes a shell 7 and an end cap assembly 10, and the end cap assembly 10 is arranged on one side of the shell 7 and covers the end opening 71 of the shell 7, so that a closed space for accommodating the electrode assembly 30 is formed inside the shell 70.

[0184] like Figure 2 and Figure 3A As shown, the end cap assembly 10 includes an end cap 10a, an electrode terminal 10c, an insulating member 10d, a sealing ring 3 and a pressure relief device 10b. The end cap 10a is used to connect with the shell 7 to close the end opening 71 of the shell 7. A through hole 11 is provided on the end cap 10a. The sealing ring 3 is used to seal the through hole 11. The insulating member 10d is arranged between the end cap 10a and the electrode assembly 30 to achieve insulation between the end cap 10a and the electrode assembly 30. Two electrode terminals 10c are arranged on the end cap 10a and are located on both sides of the through hole 11 along the length direction. At the same time, the two electrode terminals 10c are electrically connected to the positive and negative ears of the electrode assembly 30 through an adapter 20 respectively. The pressure relief device 10b is detachably arranged on the end cap 10a and inserted into the through hole 11 between the two electrode terminals 10c to achieve the through hole blocking and safety pressure relief functions.

[0185] Among them, Figure 2 as well as Figure 5-6B As shown, the end cap 10a includes an end cap body 1 and a mounting component 2. The end cap body 1 is used to connect with the housing 7. The mounting component 2 is connected to the side of the end cap body 1 away from the electrode assembly 30. Specifically, the two electrode terminals 10c are arranged on the end cap body 1, and a mounting groove 15 is provided between the two electrode terminals 10c, and the mounting component 2 is arranged in the mounting groove 15. Among them, the mounting groove 15 is recessed toward the electrode assembly 30 by the surface of the end cap body 1 away from the electrode assembly 30, and the mounting component 2 is fixed in the mounting groove 15 by tight fit, bonding, fastener connection or welding.

[0186] The installation groove 15 is provided to accommodate the installation component 2, so that the height of the installation component 2 relative to the end cover body 1 can be reduced. Figure 5 As shown, the surface of the mounting component 2 away from the electrode assembly 30 may not exceed the surface of the end cap body 1 away from the electrode assembly 30, but may be lower than and flush with the surface of the end cap body 1 away from the electrode assembly 30 to reduce the height of the battery cell 400.

[0187] like Figure 3C and Figure 4C As shown, the mounting groove 15 is constructed as a tapered groove that is wide at the top and narrow at the bottom. Therefore, the side wall of the mounting groove 15 can guide the mounting component 2 during the insertion process of the mounting component 2. At the same time, when the mounting component 2 is fixed in the mounting groove 15 by laser welding, the mounting groove 15 can also ensure that there is no gap in the laser incident path, thereby preventing welding explosion points due to gaps and improving the strength of the welding structure.

[0188] The through hole 11 passes through the mounting component 2 and the end cover body 1, and includes a first hole section 111 located on the end cover body 1 and a second hole section 26 located on the mounting component 2. The first hole section 111 extends from the bottom of the mounting groove 15 to the surface of the end cover body 1 facing the electrode assembly 30. The second hole section 26 is located on the side of the first hole section 111 away from the electrode assembly 30, and is connected to the first hole section 111. And the aperture of the second hole section 26 is larger than the aperture of the first hole section 111. In this way, when the through hole 11 is opened, liquid can be injected into the battery cell 400 through the through hole 11, or the gas inside the battery cell 400 can be discharged. Since the through hole 11 has both liquid injection and exhaust functions, there is no need to set up a liquid injection hole and an exhaust channel separately, which can reduce the number of holes on the end cover 10a, reduce the space occupied by the holes, increase space utilization, and improve the energy density of the battery cell 400.

[0189] The sealing ring 3 is arranged at one end of the first hole section 111 close to the second hole section 26, and the sealing of the through hole 11 is achieved by sealing the first hole section 111. The sealing ring 3 is covered by the pressure relief device 10b and squeezed by the pressure relief device 10b, and a sealing surface is formed between the pressure relief device 10b and the end cover body 1. In this case, the friction coefficient of the contact surface between the sealing ring 3 and the pressure relief device 10b can be set to be smaller than the friction coefficient of the contact surface between the sealing ring 3 and the end cover 10a, so as to reduce the friction force when the rotating pressure relief device 10b rotates, reduce the difficulty of assembly, and reduce the wear of the sealing ring 3. In order to reduce the friction force between the sealing ring 3 and the pressure relief device 10b, lubricating oil can be applied between the sealing ring 3 and the pressure relief device 10b, or other spacers with low friction can be set.

[0190] In order to realize the detachable connection between the pressure relief device 10b and the end cover 10a, as shown in FIG. Figure 1D-Figure 7CAs shown, in this embodiment, the pressure relief device 10b can be rotatably inserted into the second hole section 26, and the end cover 10a is provided with a first clamping portion 24, and the pressure relief device 10b is correspondingly provided with a second clamping portion 42 to achieve rotational clamping of the pressure relief device 10b and the end cover 10a, so that during the rotation of the pressure relief device 10b relative to the end cover 10a between the first position and the second position, the first clamping portion 24 and the second clamping portion 42 can be engaged or disengaged, thereby achieving the disassembly and assembly of the pressure relief device 10b on the end cover 10a, and further achieving the opening and closing of the through hole 11 by the pressure relief device 10b.

[0191] Specifically, by Figure 1D -7 It can be seen that in this embodiment, the first clamping portion 24 is a clamping groove 24a, and the second clamping portion 42 is a clamping column 42a. A clamping structure is formed between the clamping groove 24a and the clamping column 42a. When the pressure relief device 10b rotates to the first position, the clamping column 42a is completely or partially located in the clamping groove 24a to limit the displacement of the pressure relief device 10b away from the electrode assembly 30, so that the pressure relief device 10b will not fall off from the end cover 10a, and the through hole 11 is stably closed. When the pressure relief device 10b rotates to the second position, the clamping column 42a and the clamping groove 24a are misaligned along the circumference of the through hole 11, and the clamping column 42a is completely separated from the clamping groove 24a, so that the displacement of the pressure relief device 10b away from the electrode assembly 30 is no longer restricted by the end cover 10a, and the pressure relief device 10b can be removed from the end cover 10a, and the through hole 11 is opened to facilitate maintenance work such as injection, exhaust, and replacement of the pressure relief device 10b.

[0192] The first clamping part 24 and the second clamping part 42 can be engaged or disengaged by rotating the pressure relief device 10b. The structure is simple, the requirements for the matching accuracy are low, and the pressure relief device 10b can be used repeatedly. In terms of processing, the clamping column 42a is provided on the pressure relief device 10b, and the clamping groove 24a is provided on the end cover 10a. Both are easy to process and are particularly suitable for lithium-ion battery cells with smaller overall sizes. In terms of assembly and maintenance, the disassembly and assembly of the pressure relief device 10b are relatively easy, which can improve the assembly efficiency of the battery cell 400 during production and shorten the maintenance time during maintenance during use.

[0193] In addition, the through hole 11 is opened and closed by rotating the pressure relief device 10b, so that maintenance work such as injection, exhaust and replacement of the pressure relief device 10b can be performed without damaging the battery cell 400. Among them, the pressure relief device 10b is removed and the liquid is injected through the through hole 11, so that the secondary injection function can be realized, which effectively reduces the reduction of the capacity of the battery cell 400 and prolongs the service life of the battery cell 400. Removing the pressure relief device 10b and exhausting the gas through the through hole 11 can release the internal pressure of the battery cell 400, shorten the continuous action time of the gas inside the battery cell 400 on the pressure relief device 10b, and prevent the pressure relief device 10b from rupture due to premature creep, causing leakage of liquid and gas, which is conducive to prolonging the service life of the pressure relief device 10b. In addition, removing the pressure relief device 10b and replacing it can not only meet the need to replace the pressure relief device 10b after it is damaged and extend the service life of the battery cell 400, but also meet the need to regularly replace the pressure relief device 10b even though it is not damaged, thereby reducing the life requirements of the pressure relief device 10b and improving the reliability of the use of the pressure relief device 10b.

[0194] Among them, Figure 6A-6B As shown, in this embodiment, the slot 24a is formed by the mounting member 2 and the end cap body 1. Specifically, the mounting member 2 includes a mounting ring 21 and a stopper 22. The middle hollow portion of the mounting ring 21 forms a second hole section 26. The stopper 22 is connected to the inner wall of the mounting ring 21, protruding radially inward from the inner wall of the mounting ring 21, and having a gap between the surface of the mounting ring 21 facing the electrode assembly 30. In this way, as shown in FIG. Figure 5 As shown in FIG. 1 , when the mounting member 2 is installed in the mounting groove 15, a slot 24a serving as the first clamping portion 24 is formed between the stopper 22 and the bottom of the mounting groove 15. At this time, the first clamping portion 24 is a slot 24a formed by the mounting member 2 and the end cover body 1, and is combined with the mounting member 2 to form a first clamping portion 24. Figure 3C , Figure 4C , Figure 5 as well as Figure 6B It can be seen that the bottom wall of the limit platform 22, the side wall of the mounting ring 21 and the bottom wall of the mounting groove 15 respectively constitute the first groove wall 243, the second groove wall 244 and the third groove wall 245 of the clamping groove 24a, which can limit the displacement of the clamping column 42a along the height direction when the clamping column 42a is inserted.

[0195] Moreover, based on the above configuration, the card slot 24a is located on the side of the end cover 10a away from the electrode assembly 30, which is beneficial to prevent metal particles generated by friction during the rotational card connection from falling directly into the shell 7 and causing the battery cell 400 to short-circuit, which can effectively improve the working safety of the battery cell 400.

[0196] Specifically, Figure 5-6BAs shown, the limiting platform 22 is provided at one end of the mounting ring 21 away from the first hole section 111, and the limiting platform 22 is flush with the surface of the mounting ring 21 away from the first hole section 111. In this way, the height of the clamping groove 24a can be increased, which is conducive to improving the clamping strength of the first clamping portion 24 and the second clamping portion 42.

[0197] And as Figures 7A-7C In this embodiment, in order to facilitate the arrangement of the clamping column 42a and realize the blocking function of the pressure relief device 10b on the through hole 11, the pressure relief device 10b includes a main body 4 and a pressure relief member 5. The main body 4 is a disc-shaped or annular structure. The clamping column 42a is arranged on the outer wall of the main body 4 and protrudes outward from the outer wall of the main body 4 to form a cantilever structure, so that when the main body 4 is inserted into the second hole section 26, the clamping column 42a can be engaged or disengaged with the card slot 24a as the main body 4 rotates. The hollowed-out middle part of the main body 4 forms a vent 414. The pressure relief member 5 is arranged at the vent 414 to seal the vent 414. When the internal pressure of the battery cell 400 reaches the threshold, the pressure relief member 5 is destroyed to release the closure of the vent 414, so that the through hole 11 can be connected to the external environment through the vent 414, realizing the pressure relief process and playing a safety protection role.

[0198] Specifically, in this embodiment, the pressure relief member 5 is integrally provided with the main body 4. The pressure relief member 5 is connected to one end of the main body 4 away from the electrode assembly 30, and the vent 414 is sealed by sealing the external port of the vent 414. The pressure relief member 5 can be constructed as a metal layer 51 such as an aluminum sheet 522.

[0199] And, if Figure 4C as well as FIG. 7B to FIG. 7C As shown, in this embodiment, a depression 412 is provided on the pressure relief member 5, and the sealing ring 3 is located in the depression 412. Specifically, the depression 412 can be made by stamping, and the surface of the pressure relief member 5 facing the electrode assembly 30 is recessed in a direction away from the electrode assembly 30. In this way, the space occupied by the sealing ring 3 can be reduced, which is conducive to reducing the overall height of the battery cell 400 and improving the energy density of the battery cell 400.

[0200] At the same time, by Figure 7B and Figure 7C It can be seen that in this embodiment, a circle of notches 53 is provided on the pressure relief member 5, so that when the internal pressure of the battery cell 400 reaches a threshold, the notches 53 are first broken, which can achieve directional exhaust and pressure relief of the battery cell 400, and prevent the battery cell 400 from exploding due to excessive internal pressure. The notches 53 are located radially inward of the inner ring of the sealing ring 3, which can prevent the elastic force of the sealing ring 3 from causing the notches 53 to break accidentally.

[0201] In addition, if FIG. 7A to FIG. 7CAs shown, in this embodiment, at least two clamping columns 42a are provided on the outer wall of the main body 4, and the at least two clamping columns 42a are arranged at intervals along the circumference of the main body 4 and extend along the circumference of the through hole 11. In this case, Figure 5-6B As shown, the number of the limiting platforms 22 on the end cover 10a that enclose the clamping groove 24a is also at least two, and the limiting platforms 22 extend along the circumference of the through hole 11 and correspond one-to-one with the clamping columns 42a, so that at least two clamping grooves 24a are provided on the end cover 10a, and the clamping grooves 24a extend along the circumference of the through hole 11 and correspond one-to-one with the clamping columns 42a. Based on this, the pressure relief device 10b has multiple limiting supports when in the first position, which is not only conducive to improving the installation stability and firmness of the pressure relief device 10b, but also conducive to reducing the clamping force borne by a single clamping column 42a, so as to reduce the strength requirements of the clamping column 42a.

[0202] By setting the number and spacing angle of the limit platforms 22, the rotation angle of the pressure relief device 10b between the first position and the second position can be controlled. For example, when the two limit platforms 22 are arranged relatively on the mounting component 2, the pressure relief device 10b only needs to rotate 90° to rotate from the first position to the second position, or from the second position to the first position, which is conducive to improving the efficiency of disassembly and assembly. Of course, the angle between the first position and the second position of the pressure relief device 10b is not limited to 90°, for example, it can be changed within 60°-120°, and can be set according to actual needs.

[0203] Depend on Figure 5-6B It can be seen that the space between the two spaced limiting platforms 22 forms a guide groove 25, which is connected to the card slot 24a and is used to guide the card column 42a to enter and exit the card slot 24a to improve the smoothness of the rotation and clamping process. Among them, the circumferential length of the guide groove 25 can be greater than the circumferential length of the card column 42a, so as to accommodate the card column 42a when the pressure relief device 10b is in the second position. At the same time, the length of the guide groove 25 does not exceed the circumferential length of the card slot 24a, so as to maximize the clamping length of the card column 42a and the card slot 24a, and improve the limiting stability.

[0204] In addition to providing a guide groove 25 to guide the clamping column 42a to smoothly enter and exit the clamping groove 24a, as shown in FIG. Fig. 7A As shown, the column 42a can also be provided with an inclined surface 42b, and the inclined surface 42b can be used to guide the column 42a to enter and exit the slot 24a. Specifically, the inclined surface 42b is provided on the side wall of the column 42a along the circumferential direction, and is configured to gradually reduce the thickness of the side portion of the column 42a along the circumferential direction from the inside to the outside. Based on this, the inclined surface 42b can make the column 42a smoothly enter the slot 24a, without the need to adjust the height of the column 42a in advance, which can improve the assembly efficiency and prevent the column 42a from colliding with the entrance of the slot 24a, thereby facilitating the service life of the end cover assembly 10 and reducing the generation of metal chips.

[0205] The inclined surface 42b may be a plane or an arc surface, etc. In addition, the inclined surface 42b may be provided on one or both sides of the circumference of the clamping column 42a. When both sides of the circumference of the clamping column 42a are provided with inclined surfaces 42b, it is helpful to guide the clamping column 42a to enter and exit the clamping slot 24a more smoothly.

[0206] Arranging the inclined surface 42b on the clamping column 42a is easier to process. However, as an alternative, the inclined surface 42b can also be arranged on the groove wall of the clamping groove 24a, for example, it can be arranged on the first groove wall 243 or the second groove wall 244.

[0207] In order to facilitate the clamping column 42a to rotate in and out of the clamping slot 24a, the height of the clamping slot 24a can be greater than the clamping column 42a. In this way, after the clamping column 42a enters the clamping slot 24a, the clamping column 42a contacts the first groove wall 243 under the elastic force of the sealing ring 3, and at the same time, there is a gap between the bottom surface of the clamping column 42a and the second groove wall 244.

[0208] Figures 3A-3C as well as Figures 4A-4C 1 and 1 show the states of the pressure relief device 10b in the first position and the second position respectively. Figures 3A-3C As shown, when the pressure relief device 10b rotates to the first position, the clamping column 42a is inserted into the clamping groove 24a, so that the clamping groove 24a can limit the pressure relief device 10b from being separated from the end cover 10a. Figures 4A-4C As shown, when the pressure relief device 10b rotates to the second position, the clamping column 42a escapes from the clamping slot 24a and enters the guide slot 25, so that the pressure relief device 10b is no longer restricted by the clamping slot 24a, and can be removed from the end cover 10a to open the through hole 11.

[0209] Specifically, by Figure 3C It can be seen that when the pressure relief device 10b is in the first position, the clamping column 42a abuts against the first slot wall 243 of the clamping slot 24a away from the electrode assembly 30, so that the first slot wall 243 can limit the displacement of the pressure relief device 10b away from the electrode assembly 30, and prevent the pressure relief device 10b from being separated from the end cover 10a. More specifically, the first slot wall 243 includes a protrusion 243a, which protrudes toward one side of the electrode assembly 30 relative to other parts of the first slot wall 243 and abuts against the clamping column 42a, so that the first slot wall 243 abuts against the clamping column 42a through the protrusion 243a.

[0210] Furthermore, in order to reduce the resistance of the pressure relief device 10b during rotation, a gap may be provided between the second groove wall 244 and the clamping column 42a opposite to the first groove wall 243. Similarly, in order to reduce the resistance of the pressure relief device 10b during rotation, a gap may be provided between the third groove wall 245 connected between the first groove wall 243 and the second groove wall 244 and the clamping column 42a.

[0211] When the pressure relief device 10b needs to be installed, a downward force is applied to the pressure relief device 10b, and a gap is generated between the clamping column 42a and the first groove wall 243 through the deformation of the sealing ring 3. At this time, the pressure relief device 10b is rotated to allow the clamping column 42a to smoothly enter the groove 24a. After reaching the first position, the pressure relief device 10b is released, and the pressure relief device 10b moves upward under the elastic force of the sealing ring 3 until the top surface of the clamping column 42a is against the first groove wall 243. At this time, a gap may appear between the bottom surface of the clamping column 42a and the second groove wall 244 (not shown in the figure).

[0212] When the pressure relief device 10b needs to be disassembled, a downward force is applied to the pressure relief device 10b, and a gap is generated between the clamping column 42a and the first groove wall 243 through the deformation of the sealing ring 3. At this time, the pressure relief device 10b is rotated to make the clamping column 42a smoothly circumferentially misaligned with the groove 24a and located as a whole in the guide groove 25. At this time, the second position is reached, and the pressure relief device 10b can be removed for operations such as liquid injection, exhaust or replacement of the pressure relief device 10b.

[0213] The first groove wall 243, the second groove wall 244 and the third groove wall 245 can be planes or arc surfaces. When the surfaces of the first groove wall 243 and the clamping column 42a that contact each other are both planes, the contact area between the first groove wall 243 and the clamping column 42a can be increased, the stability of the clamping can be improved, and the friction between the first groove wall 243 and the clamping column 42a can be increased, which increases the difficulty of the pressure relief device 10b to rotate circumferentially relative to the end cover 10a in the clamping state.

[0214] In addition, back to Figure 7A-7C In this embodiment, in order to facilitate the rotation of the pressure relief device 10b, the pressure relief device 10b further includes an operating portion 411, which is used to receive external operations to drive the pressure relief device 10b to rotate. By providing the operating portion 411, it is convenient to rotate the pressure relief device 10b through the cooperation of the tooling and the operating portion 411, and it is convenient to apply external force when disassembling the pressure relief device 10b, and it is easy to control the rotation angle of the pressure relief device 10b.

[0215] Specifically, Fig. 7AAs shown, in this embodiment, at least two bosses 411a are provided on the surface of the pressure relief member 5 away from the electrode assembly 30, and the at least two operating parts 411 are arranged at intervals along the circumference of the through hole 11, and the operating part 411 includes a groove 411b located between two adjacent bosses 411a. At this time, the tooling can be inserted into the groove 411b to rotate the pressure relief device 10b. The assembly process of the battery cell 400 of this embodiment can be as follows: first, the mounting component 2 is placed in the mounting groove 15 and welded; then, the electrolyte is injected from the through hole 11, and the sealing ring 3 is installed after the injection is completed; then, the pressure relief device 10b is placed in the second position on the end cover 10a, so that the pressure relief device 10b covers at least part of the sealing ring 3, and the clamping column 42a of the pressure relief device 10b is circumferentially misaligned with the clamping groove 24a of the end cover 10a, and disengaged from each other; then, a special tool is used to clamp the groove 4 11b, and exert a force downward so that there is a gap between the clamping column 42a and the first groove wall 243 of the groove 24a, and at the same time rotate the pressure relief device 10b to turn the pressure relief device 10b from the second position to the first position, so that the clamping column 42a is clamped in the groove 24a to limit the separation of the pressure relief device 10b from the end cover 10a; after rotating into place, release the pressure relief device 10b, and the pressure relief device 10b then rises under the elastic force of the sealing ring 3, so that the pressure relief device 10b abuts against the first groove wall 243.

[0216] When it is necessary to perform maintenance operations such as secondary liquid injection, exhaust or replacement of the pressure relief device 10b on the battery cell 400, use a tool to clamp the groove 411b, rotate the pressure relief device 10b in the opposite direction, turn the pressure relief device 10b from the first position back to the second position, remove the pressure relief device 10b, and remove the sealing ring 3. After the operations such as liquid injection and exhaust are completed, repeat the above-mentioned assembly process to complete the maintenance of the battery cell 400.

[0217] Next, combine Figure 8-10A In order to simplify the description, only the differences between the second embodiment and the first embodiment are described.

[0218] like Figure 8-10A As shown, the second embodiment differs from the aforementioned first embodiment mainly in that the structure of the pressure relief device 10b is different.

[0219] Specifically, by Figure 8-10AIt can be seen that in this second embodiment, the main body 4 and the pressure relief component 5 of the pressure relief device 10b are no longer arranged in an integrated manner, but are arranged separately. Among them, the pressure relief component 5 still adopts a metal layer 51 structure such as an aluminum sheet 522, but it is no longer connected to the end of the main body 4 away from the electrode assembly 30, but is located between the main body 4 and the sealing ring 3. At this time, the pressure relief component 5 covers the sealing ring 3, and by closing the opening of the end of the vent 414 of the main body 4 close to the electrode assembly 30 (that is, the lower port of the vent 414), the vent 414 is closed, and then the through hole 11 is closed. After the pressure relief component 5 is destroyed, the through hole 11 can be connected to the external environment through the vent 414 to realize the liquid injection and gas replenishment process.

[0220] Since the pressure relief member 5 is no longer connected to the main body 4, when the main body 4 rotates, the pressure relief member 5 is no longer driven to rotate together, and there is relative rotation between the main body 4 and the pressure relief member 5. In this case, in order to reduce the wear of the pressure relief member 5 during the rotation of the main body 4, as shown in FIG. Figure 8 As shown, the pressure relief device 10b of the second embodiment also includes a separation ring 6, which is arranged between the main body 4 and the pressure relief member 5. The separation ring 6 separates the main body 4 and the pressure relief member 5, reduces the wear of the pressure relief member 5 during the rotation of the main body 4, and protects the pressure relief member 5.

[0221] Fig. 10B and Fig. 10C It also shows Fig. 10A A first variation and a second variation of the pressure relief member 5 are shown.

[0222] Among them, Fig. 10B and Fig. 10C As shown, in the first and second variants, the pressure relief member 5 no longer adopts a single-layer structure, but a multi-layer structure. Specifically, the pressure relief member 5 is an aluminum-plastic film 52, which includes a first protective layer 521 made of nylon or PET material, a second protective layer 523 made of polypropylene material, and a metal layer 51 such as an aluminum sheet 522 located between the first protective layer 521 and the second protective layer 523.

[0223] Since the aluminum-plastic film 52 has electrolyte penetration resistance and waterproof capability comparable to metal materials, and has better deformation resistance than the single metal layer 51 with notches 53, damage and leakage caused by accidental deformation can be effectively prevented.

[0224] Compare Fig. 10B and Fig. 10C It can be seen that the difference between these two variants is that Fig. 10B In the first variant shown, no notch 53 is provided on the metal layer 51, but Fig. 10CIn the second variation shown, a notch 53 is provided on the metal layer 51 , and the notch 53 is no longer an annular groove 531 , but a cross-shaped groove 532 .

[0225] Compared with the first variant, the second variant further has notches 53 on the metal layer 51 , which can reduce the withstand voltage of the aluminum-plastic film 52 , thereby meeting the safety protection requirements of the battery cell 400 with low burst pressure.

[0226] When the pressure relief member 5 is an aluminum-plastic film 52, the separation ring 6 disposed between the pressure relief member 5 and the main body 4 can prevent the aluminum-plastic film 3 from being worn during the rotation and engagement of the main body 4, thereby preventing the aluminum-plastic film 3 from failing to seal due to wear.

[0227] Next, let’s introduce Figure 12-17 The third embodiment is shown.

[0228] like Figure 12-17 As shown, the difference between the third embodiment and the aforementioned embodiments mainly lies in that the pressure relief device 10b no longer includes only one pressure relief member 5, but includes at least two pressure relief members 5, and the at least two pressure relief members 5 are interconnected, and when the internal pressure of the battery cell 400 reaches a threshold value, the pressure relief device 10b is destroyed at the connection between these pressure relief members 5.

[0229] Specifically, by Figure 15-17 It can be seen that in the third embodiment, the pressure relief device 10b includes two pressure relief members 5, and the two pressure relief members 5 partially overlap and are connected by heat sealing at the overlapping portion 524. More specifically, the pressure relief member 5 is an aluminum-plastic film 52.

[0230] Based on the above configuration, the two aluminum-plastic films 52 are heat-sealed to form an aluminum-plastic film seal. During the heat-sealing process, the seal strength can be controlled to be much lower than the compressive strength of the aluminum-plastic film 52 itself, so a pressure relief and explosion-proof process with a lower threshold can be achieved. In addition, compared with the method of providing a notch 53 on the metal layer 51 of the aluminum-plastic film 52, the heat-sealing process is easier to operate, and the difficulty of controlling the notch 53 on the metal layer 51 can be avoided, thereby improving production efficiency.

[0231] In addition, if Figure 12-Figure 15 As shown, in the third embodiment, the overlapping portion 524 protrudes toward the side away from the sealing ring 3 relative to the rest of the pressure relief member 5, and the separation ring 6 is provided with a receiving groove 61, and the overlapping portion 524 is received in the receiving groove 61. Based on this, it can be prevented that the uneven force between the main body 4 and the pressure relief member 5 is caused by the protrusion of the overlapping portion 524.

[0232] At the same time, if Fig.17As shown, in the third embodiment, the overlapping portion 524 is bent toward the side close to the electrode assembly 30, so that the height of the overlapping portion 524 is reduced relative to the case where the overlapping portion 524 is not bent, which is beneficial to reducing the height of the end cover assembly 10, improving the space utilization of the battery cell 400 in the height direction, and improving the energy density of the battery cell 400.

[0233] As a variation of the pressure relief device 10b in the third embodiment, Fig.18 As shown, although the two pressure relief members 5 are still partially overlapped, the overlapping portion 524 is no longer bent, and the pressure relief member 5 is no longer a multi-layer structure, but only a single-layer structure.

[0234] As another variation of the pressure relief device 10b in the third embodiment, Fig.19 As shown, although the two pressure relief members 5 are still of a multi-layer structure, the two pressure relief members 5 no longer overlap, but are butted against each other.

[0235] Next, Figure 20-23 The fourth embodiment shown is described below.

[0236] like Figure 20-23 As shown, the main difference between the fourth embodiment and the aforementioned embodiments is that the main body 4 is no longer inserted into the mounting component 2, but is sleeved on the outside of the mounting component 2, and the first clamping portion 24 is no longer formed by the mounting component 2 and the end cover body 1, but is arranged on the mounting component 2 and located on the outer side wall of the mounting component 2. Correspondingly, the second clamping portion 42 is arranged on the inner side wall of the main body 4.

[0237] By sleeve-arranging the pressure relief device 10b outside the mounting component 2, it is convenient for the operator to directly apply external force to the pressure relief device 10b to rotate it, which is easy to operate and does not require the design of special tooling, thereby improving assembly and maintenance efficiency. In addition, since the pressure relief device 10b is sleeved outside the mounting component 2, the mounting component 2 generally needs to protrude from the surface of the end cover body 1, and the first clamping portion 24 is arranged on the outer side wall of the mounting component 2, which can improve the strength of the end cover body 1 on the one hand, and help reduce the thickness of the end cover body 1 on the other hand.

[0238] Among them, Fig.21 and Fig. 22As shown, the mounting component 2 includes a mounting ring 21 and a base 23. The base 23 is fixed in the mounting groove 15. For example, the base 23 is fixed in the mounting groove 15 by tight fit, bonding, welding or fastener connection. The mounting ring 21 is connected to the end of the base 23 away from the electrode assembly 30. In this way, the mounting ring 21 protrudes from the surface of the end cover body 1 away from the electrode assembly 30, which is convenient for the sleeve installation of the pressure relief device 10b. In addition, by arranging the base 23 in the mounting groove 15, the overall height of the end cover assembly 10 can be reduced to a certain extent. At the same time, the provided base 23 also facilitates increasing the installation stability of the mounting ring 21.

[0239] like Fig. 22 and Fig.23 As shown, in the fourth embodiment, the first clamping portion 24 is a clamping groove 24a provided on the outer side wall of the mounting ring 21, and correspondingly, the second clamping portion 42 is a clamping post 42a provided on the inner side wall of the main body 4. When the pressure relief device 10b rotates to the first position, the clamping post 42a is embedded in the clamping groove 24a, so that the pressure relief device 10b is installed on the end cover 10a. Specifically, as Fig. 22 As shown, the slot 24a is located on a side of the mounting ring 21 close to the base 23, with the top surface of the base 23 serving as the second slot wall 244. The slot 24a includes a first slot 241, and the first slot 241 extends along the circumference of the mounting ring 21. In addition, the slot 24a also includes a second slot 242. The second slot 242 is connected to the first slot 241 and is located above the first slot 241, that is, the second slot 242 is located on a side of the first slot 241 away from the base 23. In this case, when the pressure relief device 10b rotates to the first position, the post 42a is embedded in the second slot 242, and there is a gap between the post 42a and the base 23, so that the pressure relief device 10b has less resistance during the rotation process.

[0240] At least two clamping grooves 24a may be arranged at intervals along the circumferential direction, and correspondingly, at least two clamping columns 42a may also be arranged along the circumferential direction. Fig. 22 As shown, a guide groove 25 can be provided between adjacent clamping grooves 24a to guide the clamping column 42a to smoothly enter and exit the clamping groove 24a. Specifically, the top of the guide groove 25 passes through the top of the mounting ring 21. The bottom of the guide groove 25 is connected with the clamping groove 24a. More specifically, the bottom of the guide groove 25 is connected with the side of the first clamping groove 241 away from the second clamping groove 243, so that the guide groove 25 is connected with the clamping groove 24a to form an L-shaped groove, so that when the main body 4 is sleeved on the mounting ring 21 and rotated, the clamping column 42a can smoothly enter the clamping groove 24a under the guidance of the guide groove 25 and engage with the second clamping groove 243.

[0241] In addition, if Fig.21 and Fig.23As shown, in the fourth embodiment, the arrangement of the pressure relief member 5 is similar to that of the first embodiment, and is still integrally arranged at the end of the main body 4 away from the electrode assembly 30; while the arrangement of the sealing ring 3 is changed, the sealing ring 3 is no longer arranged at the end of the first hole section 111 close to the second hole section 26, but is instead arranged in the pressure relief device 10b, and specifically located between the clamping column 42a and the pressure relief member 5, so that the pressure relief device 10b can squeeze the sealing ring 3 to improve the sealing effect.

[0242] The assembly process of the battery cell 400 of the fourth embodiment can be as follows:

[0243] First, the mounting component 2 is placed in the mounting groove 15 and welded; then, the electrolyte is injected from the through hole 11; then, the sealing ring 3 is attached to the lower surface of the pressure relief member 5; finally, the pressure relief device 10b is sleeved on the outside of the mounting component 2. During the sleeve insertion process, the clamping column 42a is allowed to enter the clamping groove 24a through the guide groove 25. After the clamping column 42a reaches the clamping groove 24a, a downward force is applied to the pressure relief device 10b, and the pressure relief device 10b is rotated to make the clamping column 42a move in the clamping groove 24a until the pressure relief device 10b is rotated to the first position and the clamping column 42a reaches the second clamping groove 243. Then, the pressure relief device 10b is released, so that the pressure relief device 10b rises to abut against the top wall of the second clamping groove 243 under the action of the elastic force of the sealing ring 3 to limit the separation of the pressure relief device 10b from the end cover 10a, and the assembly is completed.

[0244] When the battery cell 400 needs to be injected with liquid for the second time, the pressure relief device 10b is rotated in the opposite direction to move the pressure relief device 10b from the first position to the second position, and the pressure relief device 10b and the sealing ring 3 are removed to inject liquid. After the injection is completed, the above-mentioned assembly process is repeated to complete the maintenance of the battery cell 400.

[0245] Based on the foregoing introduction, it can be known that each embodiment of the present application has an integrated liquid-injected explosion-proof structure, and can achieve rapid disassembly and assembly of the pressure relief device 10b without damaging the battery cell 400, and perform maintenance operations such as liquid injection, exhaust and replacement of the pressure relief device, thereby effectively improving the energy density of the battery cell 400, extending the service life of the battery cell 400, and improving the working reliability of the battery cell 400, thereby effectively improving the performance of the battery cell 400.

[0246] Based on the improvements of the end cap assembly 10 in the above embodiments, refer to Fig.24 The present application also provides a housing assembly 700 for a battery cell 400, the housing assembly 700 comprising:

[0247] The shell 7 is used to connect with the end cover 10a to form a shell 70 of the battery cell 400. The shell 7 is provided with a through hole 11 and a first clamping portion 24. The first clamping portion 24 is arranged along the circumference of the through hole 11 and is located on a side of the shell 7 away from the inside of the battery cell 400;

[0248] A sealing ring 3, used for sealing the through hole 11; and

[0249] The pressure relief device 10b covers at least a portion of the sealing ring 3 and closes the through hole 11, and is configured to release the seal of the through hole 11 when the air pressure in the housing 7 reaches a preset pressure;

[0250] Among them, the pressure relief device 10b is rotatable and includes a second clamping portion 42. When the pressure relief device 10b rotates to the first position, the second clamping portion 42 is clamped with the first clamping portion 24 to limit the separation of the pressure relief device 10b from the shell 7; when the pressure relief device 10b rotates to the second position, the second clamping portion 42 is disengaged from the first clamping portion 24 to achieve the separation of the pressure relief device 10b from the shell 7.

[0251] Based on the above configuration, the through hole 11, the sealing ring 3 and the pressure relief device 10b are no longer arranged on the end cover 10a, but are arranged on the housing 7 connected to the end cover 10a. The pressure relief device 10b can select any embodiment described in the end cover assembly 10 above.

[0252] Since the shell 7 does not need to be provided with other components such as the electrode terminal 10c and the end cover temperature collection structure like the end cover 10a, the free area of ​​the shell 7 is relatively large, which is more convenient for the arrangement of the through hole 11, the sealing ring 3 and the pressure relief device 10b. In addition, the through hole 11 is arranged on the shell 7 with a larger free area, which is also convenient for increasing the size of the through hole 11 and the pressure relief device 10b, which is conducive to further improving the injection efficiency, the structural strength of the pressure relief device 10b, and the sealing reliability of the pressure relief device 10b to the through hole 11. At the same time, this can also make the disassembly and assembly of the pressure relief device 10b have a larger operating space, thereby improving the disassembly and assembly efficiency.

[0253] Specifically, Fig.24 As shown, the through hole 11 is provided on the wall surface of the housing 7 adjacent to the end cover 10a, so that the battery cell 400 can be stably placed with the end cover 10a facing upward. For example, the through hole 11 is provided on the wall surface of the housing 7 adjacent to the largest side surface, so that when multiple battery cells 400 are placed horizontally or vertically to form a battery module 300, the largest side surfaces of adjacent battery cells 400 can still be kept in contact, thereby making the structure of the battery module 300 more stable and reducing the volume.

[0254] The shell assembly 700 provided in the present application can flexibly and conveniently realize the repeated disassembly and assembly of the pressure relief device 10b, so that when the electrolyte is insufficient or the electrolyte performance is reduced, the pressure relief device 10b can be conveniently removed to perform secondary injection and discharge the gas in the battery cell 400. After the secondary injection is completed, the through hole 11 can be reliably closed, thereby ensuring the reliability of the battery cell 400 after the secondary injection and keeping the appearance of the battery cell 400 consistent with that before the injection.

[0255] When including the shell assembly 700 of the present application, the housing 70 may no longer include the end cover assembly 10 in the aforementioned embodiments, but only include the end cover 10a.

[0256] In addition, the present application also provides a method for injecting liquid into a battery cell 400, referring to Fig.25 , the injection method comprises:

[0257] Step S101, injecting electrolyte into the battery cell 400 through the housing 7 of the housing 70 of the battery cell 400 or the through hole 11 on the end cover 10a;

[0258] Step S102, placing the pressure relief device 10b at a second position on the housing 7 or the end cover 10a, so that the pressure relief device 10b covers at least a portion of the sealing ring 3, and the second clamping portion 42 of the pressure relief device 10b is disengaged from the first clamping portion 24 of the housing 70 which is arranged along the circumference of the through hole 11 and is located on the side of the housing 70 away from the inside of the battery cell 400;

[0259] Step S103, rotating the pressure relief device 10b from the second position to the first position, so that the second clamping portion 42 is clamped with the first clamping portion 24, so as to limit the pressure relief device 10b from being separated from the housing 7 or the end cover 10a.

[0260] Compared with the traditional method of sealing the injection hole by laser welding, the present application can not only omit the injection hole welding sealing process, but also omit the subsequent cleaning of welding slag caused by welding and drying of the residual liquid caused by the cleaning. Therefore, the present application improves the production efficiency of the battery cell. The present application realizes the engagement or disengagement of the second clamping portion 42 and the first clamping portion 24 by rotating the pressure relief device 10b, which is simple and quick. During the assembly process of the battery cell 400, the assembly efficiency of the pressure relief device 10b can be improved, thereby further improving the production efficiency of the battery cell.

[0261] Furthermore, if Fig.26 As shown, before placing the pressure relief device 10b at the second position on the housing 7 or the end cover 10a in step S102, the liquid injection method further includes:

[0262] Step S102A: Install the sealing ring 3 on the housing 70 .

[0263] In this embodiment, the sealing ring 3 is installed on the housing 70 in advance, and the sealing ring 3 can be directly covered after the pressure relief device 10b is installed, or a pressing force is generated on the sealing ring 3 to achieve a better sealing effect on the through hole 11. Figure 1D-Figure 19 In each embodiment shown, the sealing ring 3 can be pre-installed on the end cover 10a; Figure 20-23 In the embodiment shown, the sealing ring 3 can be pre-attached to the lower surface of the pressure relief member 5 .

[0264] Continue to refer to Fig.26 In some embodiments, the liquid injection method further comprises:

[0265] Step S104, rotating the pressure relief device 10b from the first position to the second position, so that the second clamping portion 42 is disengaged from the first clamping portion 24;

[0266] Step S105, separating the pressure relief device 10b from the housing 7 or the end cover 10a.

[0267] The pressure relief device 10b is removed from the housing 70 to facilitate maintenance operations such as filling, exhausting or replacing the pressure relief device 10b. For example, after step S015, step S106 can be performed to add electrolyte to the battery cell 400 through the through hole 11 to achieve a secondary filling function.

[0268] After the maintenance is completed, the pressure relief device 10b is installed through steps S101-S103, and the through hole 11 can be closed, which is simple and convenient.

[0269] This injection method can flexibly and conveniently realize the repeated disassembly and assembly of the injection device 10b, and can reliably close the through hole 11 after the second injection is completed, thereby ensuring the reliability of the battery cell 400 after the second injection, and can also make the appearance of the battery cell consistent with that before the injection; moreover, the maintenance time can be shortened during the second injection, and when the performance of the battery cell 400 decreases, the liquid can be replenished in time to ensure the working performance of the battery cell 400.

[0270] In addition, after the pressure relief device 10b is separated from the shell 7 or the end cover 10a in step S105, the sealing ring 3 can also be removed first to facilitate the pouring of the electrolyte in the shell 70 and prevent the electrolyte from flowing onto the sealing ring 3, so as to keep the sealing ring 3 clean and extend its service life.

[0271] Finally, the present application also provides a liquid injection device 600, which is used to inject liquid into the battery cell 400 and can be used to implement the above-mentioned liquid injection method. Fig. 27 As shown, in some embodiments, the injection device 600 includes:

[0272] The liquid injection mechanism 601 is configured to inject the electrolyte into the housing through the through hole 11 provided on the housing 70; and

[0273] The first disassembly and assembly mechanism 602 is configured to rotate the pressure relief device 10b from the second position to the first position when the pressure relief device 10b is in the second position, so that the second clamping portion 42 of the pressure relief device 10b and the first clamping portion 24 on the outer shell 70 change from a disengaged state to a clamping state, so as to limit the separation of the pressure relief device 10b from the shell 7 or the end cover 10a of the outer shell 70.

[0274] Compared with the conventional method of sealing the injection hole by laser welding, the present application can not only avoid the injection hole welding sealing process, but also avoid the cleaning of welding slag and drying of the residual liquid caused by welding. The injection device 600 can simply and efficiently produce the battery cell 400, thereby improving the production efficiency of the battery cell 40.

[0275] Continue to refer to Fig. 27 In some embodiments, the first disassembly mechanism 602 is further configured to rotate the pressure relief device 10b from the first position to the second position so that the second clamping portion 42 is disengaged from the first clamping portion 24 to facilitate removal of the pressure relief device 10b from the housing 70.

[0276] In addition, refer to Fig. 27 In some embodiments, the injection device 600 further includes a second disassembly mechanism 603, which is configured to install the sealing ring 3 on the housing 70, or remove the sealing ring 3 from the housing 70. For example, after the pressure relief device 10b is removed from the housing 70, the sealing ring 3 is removed from the housing 70. Based on this, the sealing ring 3 can be conveniently disassembled and assembled during the battery cell maintenance process such as battery cell assembly and secondary injection, thereby improving the disassembly efficiency, reducing the pollution to the sealing ring 3, and increasing the service life of the sealing ring 3.

[0277] The liquid injection device 600 provided in the present application can flexibly and conveniently assist in the disassembly and assembly of the pressure relief device 10b during the battery cell production and assembly and secondary liquid injection and other battery cell maintenance processes. It is simple to operate, which is beneficial to improving the assembly efficiency of the battery cell 400 and shortening the maintenance time required for the battery cell 400, so that the battery cell 400 can be replenished in time when the performance of the battery cell 400 is degraded to ensure the working performance of the battery cell 400.

[0278] The features of the above-mentioned protected subjects and embodiments of the present application can refer to each other. If the structure permits, those skilled in the art can also flexibly combine the technical features in different embodiments to form more embodiments.

[0279] The above is a detailed introduction to a battery cell end cover assembly, a battery cell, and a device using a battery cell provided by the present application. Specific embodiments are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. An end cap assembly (10) for a battery cell (400), the end cap assembly (10) comprising: An end cover (10a) provided with a through hole (11) for injecting electrolyte and a first clamping portion (24), wherein the first clamping portion (24) is arranged along the circumference of the through hole (11) and is located on a side of the end cover (10a) away from the interior of the battery cell (400); A sealing ring (3) for sealing the through hole (11); and a pressure relief device (10b), covering at least a portion of the sealing ring (3) and sealing the through hole (11), and the pressure relief device is used to be destroyed when the internal pressure of the battery cell (400) reaches a threshold value, so as to release the sealing of the through hole (11) and release the internal pressure of the battery cell (400); The pressure relief device (10b) is rotatable and comprises a second clamping portion (42); when the pressure relief device (10b) is rotated to a first position, the second clamping portion (42) is clamped with the first clamping portion (24) to limit the pressure relief device (10b) from being separated from the end cover (10a); when the pressure relief device (10b) is rotated to a second position, the second clamping portion (42) is disengaged from the first clamping portion (24) to achieve separation of the pressure relief device (10b) from the end cover (10a); The first clamping portion (24) is one of the clamping slot (24a) and the clamping column (42a), and the second clamping portion (42) is the other of the clamping slot (24a) and the clamping column (42a).

2. The end cap assembly (10) according to claim 1, wherein: The pressure relief device (10b) comprises a main body (4) and a pressure relief piece (5), wherein the main body (4) is connected to the second clamping portion (42), the pressure relief piece (5) closes the through hole (11), and the pressure relief piece (5) is used to be destroyed when the internal pressure of the battery cell (400) reaches the threshold value, so as to release the internal pressure.

3. The end cap assembly (10) according to claim 2, wherein: The pressure relief component (5) is arranged integrally or separately from the main body (4).

4. The end cap assembly (10) according to claim 3, wherein: The pressure relief component (5) is arranged separately from the main body (4), and the pressure relief component (5) is arranged between the main body (4) and the sealing ring (3).

5. The end cap assembly (10) according to claim 4, wherein: The pressure relief device (10b) further comprises a separation ring (6), wherein the separation ring (6) is arranged between the main body (4) and the pressure relief component (5) and is used to separate the main body (4) from the pressure relief component (5) so as to protect the pressure relief component (5).

6. The end cap assembly (10) according to claim 5, wherein: The separation ring (6) is attached to the pressure relief member (5).

7. The end cap assembly (10) according to claim 3, wherein: The pressure relief component (5) comprises a metal layer (51) and a protective layer (52a); the protective layer (52a) and the metal layer (51) are stacked, and the ductility of the protective layer (52a) is greater than the ductility of the metal layer (51).

8. The end cap assembly (10) according to claim 2, wherein: The pressure relief device (10b) comprises at least two pressure relief members (5) connected to each other, and when the internal pressure of the battery cell (400) reaches the threshold value, the interconnected parts of the at least two pressure relief members (5) are opened to release the internal pressure.

9. The end cap assembly (10) according to claim 8, wherein: The at least two pressure relief components (5) are butted against each other or partially overlapped.

10. The end cap assembly (10) according to claim 9, wherein: The at least two pressure relief members (5) partially overlap, and the overlapping portion (524) of the at least two pressure relief members (5) protrudes toward a side away from the sealing ring (3) relative to the remaining portion of the at least two pressure relief members (5).

11. The end cap assembly (10) according to claim 10, wherein: The overlapping portions (524) of the at least two pressure relief members (5) are bent to reduce the height of the overlapping portions (524).

12. The end cap assembly (10) according to claim 10, wherein: The separation ring (6) of the pressure relief device (10b) is provided with a receiving groove (61), and the overlapping portion (524) of the at least two pressure relief members (5) is received in the receiving groove (61).

13. The end cap assembly (10) according to claim 8, wherein: The at least two pressure relief components (5) are connected by heat sealing.

14. The end cap assembly (10) according to claim 3, wherein: The pressure relief component (5) is an aluminum-plastic film (52).

15. The end cap assembly (10) according to any one of claims 1 to 14, wherein: The end cover assembly (10) further comprises a guide groove (25), wherein the guide groove (25) is in communication with the clamping groove (24a), and during the rotation of the pressure relief device (10b), the clamping column (42a) enters and exits the clamping groove (24a) via the guide groove (25).

16. The end cap assembly (10) according to any one of claims 1 to 14, wherein: The pressure relief device (10b) is provided with a sink groove (412), and the sealing ring (3) is located in the sink groove (412).

17. A housing assembly (700) for a battery cell (400), comprising: A shell (7), the shell (7) being used to be connected with the end cover (10a) to form an outer shell (70) of a battery cell (400), the shell (7) being provided with a through hole (11) and a first clamping portion (24), the first clamping portion (24) being arranged along the circumference of the through hole (11) and being located on a side of the shell (7) away from the interior of the battery cell; A sealing ring (3) for sealing the through hole (11); and a pressure relief device (10b), covering at least a portion of the sealing ring (3) and sealing the through hole (11), and being configured to release the seal of the through hole (11) when the air pressure in the housing (7) reaches a preset pressure; The pressure relief device (10b) is rotatable and comprises a second clamping portion (42); when the pressure relief device (10b) is rotated to a first position, the second clamping portion (42) is clamped with the first clamping portion (24) to limit the pressure relief device (10b) from being separated from the housing (7); when the pressure relief device (10b) is rotated to a second position, the second clamping portion (42) is disengaged from the first clamping portion (24) to achieve separation of the pressure relief device (10b) from the housing (7); The first clamping portion (24) is one of the clamping slot (24a) and the clamping column (42a), and the second clamping portion (42) is the other of the clamping slot (24a) and the clamping column (42a).

18. A battery cell (400), comprising: An electrode assembly (30) and a housing (70) for accommodating the electrode assembly (30), the housing (70) comprising a shell (7) and an end cap assembly (10) according to any one of claims 1 to 16, the shell (7) having an end opening (71), and the end cap assembly (10) covering the end opening (71) of the shell (7); or, An electrode assembly (30) and a shell (70) for accommodating the electrode assembly (30), the shell (70) comprising an end cover (10a) and a shell assembly (700) as claimed in claim 17, the shell (7) having an end opening (71), and the end cover (10a) covering the end opening (71) of the shell (7).

19. A battery (200) comprising at least two battery cells (400) according to claim 18.

20. An electrical device (100), comprising the battery cell (400) according to claim 18, wherein the battery cell (400) is used to provide electrical energy.

21. A method for injecting liquid into a battery cell (400), comprising: Injecting electrolyte into the interior of the battery cell (400) through a through hole (11) on the shell (7) of the outer shell (70) of the battery cell (400) or the end cover (10a); The pressure relief device (10b) is placed at a second position on the housing (7) or the end cover (10a), so that the pressure relief device (10b) covers at least a portion of the sealing ring (3), and the second clamping portion (42) of the pressure relief device (10b) is disengaged from a first clamping portion (24) on the housing (70) which is arranged along the circumference of the through hole (11) and is located on a side of the housing (70) away from the inside of the battery cell (400), wherein the first clamping portion (24) is one of the clamping slot (24a) and the clamping column (42a), and the second clamping portion (42) is the other of the clamping slot (24a) and the clamping column (42a); The pressure relief device (10b) is rotated from the second position to the first position so that the second clamping portion (42) is clamped with the first clamping portion (24) to limit the separation of the pressure relief device (10b) from the housing (7) or the end cover (10a).

22. The liquid injection method according to claim 21, further comprising: Before placing the pressure relief device (10b) on the housing (7) or the end cover (10a), the sealing ring (3) is installed on the outer shell (70).

23. The liquid injection method according to claim 21 or 22, further comprising: Rotating the pressure relief device (10b) from the first position to the second position so that the second clamping portion (42) is disengaged from the first clamping portion (24); The pressure relief device (10b) is separated from the housing (7) or the end cover (10a).

24. A liquid injection device (600), used for a battery cell (400), comprising: A liquid injection mechanism (601) configured to inject electrolyte into the housing (70) through a through hole (11) provided on the housing (70); and The first disassembly and assembly mechanism (602) is configured to rotate the pressure relief device (10b) from the second position to the first position when the pressure relief device (10b) is in the second position, so that the second clamping portion (42) of the pressure relief device (10b) and the first clamping portion (24) on the housing (70) change from a disengaged state to a clamping state, so as to limit the separation of the pressure relief device (10b) from the shell (7) or the end cover (10a) of the housing (70), wherein the first clamping portion (24) is one of the clamping slot (24a) and the clamping column (42a), and the second clamping portion (42) is the other of the clamping slot (24a) and the clamping column (42a).

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